Abstract:
A phacoemulsification needle ( 100, 100 A,  100 B,  1000, 100 D,  200, 200 A) is provided for emulsifying body tissue. The needle ( 100, 100 A,  100 B,  1000, 100 D,  200, 200 A) is adapted to be attached to a phacoemulsification handpiece that imparts a vibration to the needle ( 100, 100 A,  100 B,  100 C,  100 D,  200, 200 A). The needle ( 100, 100 A,  100 B,  1000,   100 D,  200, 200 A) has a body ( 104, 220, 220 A) with a distal end ( 99 ), a proximal end ( 106 ), and an aspiration passage ( 124 ) extending between the proximal and distal ends ( 99, 106 ). The aspiration passage ( 124 ) defines a longitudinally-extending central body axis ( 110, 110 A,  110 B,  1100, 110 D). The aspiration passage ( 124 ) is enlarged at the distal end ( 99 ) to define a tip ( 102, 102 A,  102 B,  1020, 102 D,  210, 210 A).

Description:
FIELD OF THE INVENTION 
       [0001]    This disclosure relates to surgical instruments used in ophthalmic surgery and, more particularly, to phacoemulsification apparatuses. 
       BACKGROUND OF THE INVENTION 
       [0002]    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. 
         [0003]    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, Similarly, efforts have been made to accomplish the removal of the diseased lens through an equally small incision. 
         [0004]    One such removal technique is known as phacoemulsification. A typical phacoemulsification tool includes a handpiece attached to a proximal end of a hollow needle. In the handpiece, an electrical energy is applied to a piezoelectric crystal to vibrate the distal, working end of the needle at ultrasonic frequencies in order to fragment the diseased lens into small enough particles to be aspirated from the eye through an aspiration passage in the hollow needle. Commonly, an infusion sleeve is mounted around the needle at the distal end to supply irrigating liquids to the eye in order to aid in flushing and aspirating the lens particles. 
         [0005]    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 may be permanent because these cells do not regenerate. Some benefits of using as small an incision as possible during such surgery are the minimization of leakage of liquid during and after surgery to help prevent tissue collapse, faster healing time, and decreased post-operative astigmatism. 
         [0006]    Many phacoemulsification needles and tips are designed for use with handpieces that vibrate the needle longitudinally at relatively low frequencies. In addition to longitudinal vibration, certain handpieces impart a torsional motion to the needle at an oscillation frequency of about 100 cycles per second. There are also handpieces that provide torsional oscillation of the phacoemulsification tip at frequencies of about 32,000 cycles per second. 
         [0007]    Use of the torsional-type handpiece has called for phacoemulsification needle tip designs differing from those used with the longitudinal-type handpiece. For example, needles have been designed with tips that are shaped, swaged and angled to take advantage of the needle motion created by the handpiece. 
         [0008]    There are known phacoemulsification systems, such as the Infiniti Vision System manufactured by Alcon Laboratories of Ft. Worth, Texas, which allow the surgeon to choose between using torsional motion, longitudinal motion, or a blend thereof with a single handpiece. Other common systems include the Sovereign® System, Whitestar Signature® System, Signature Ellips® FX System manufactured by Abbott Laboratories of Abbott Park, Ill. and the Stellar&#39;s® System manufactured by Bausch &amp; Lomb of Rochester, N.Y. Common frequencies for longitudinal oscillation range from 29 Hz to 43 Hz. Common frequencies for torsional oscillation range from 31 Hz to 38 Hz. A common blended setting uses torsional motion two-thirds of the time, and longitudinal motion one-third of the time. It is believed that the “blended” motion produces a more three-dimensional effect because of the back-and-forth motion imparted during longitudinal phacoemulsification and the eccentric motion produced at the tip during torsional phacoemulsification. 
         [0009]    Many surgeons favor phacoemulsification needles having the straight tip design commonly used with longitudinal handpieces. The great majority of surgeons use longitudinal handpieces rather than the torsional handpieces, often because torsional phacoemulsification equipment is more expensive than longitudinal equipment, and thus these surgeons find themselves unable to take advantage of the enhanced phacoemulsification results claimed by the torsional phacoemulsification systems. 
       SUMMARY OF THE INVENTION 
       [0010]    The inventors herein have found that forming a needle tip in an off-axis position relative to the axis of the aspiration passage extending through the needle body causes eccentric motion or “wobble” during torsional phacoemulsification and improves the efficiency of phacoemulsification while retaining the straight-tip configuration. Surprisingly, the inventors have also found that forming the tip in such an off-axis position also increases the efficiency of phacoemulsification when using a longitudinal handpiece. Preliminary clinical examinations indicate that using an off-axis needle with a longitudinal handpiece may be more efficient than using the same needle with a torsional hand piece providing 100% torsional action, where efficiency is measured by the energy dissipated during phacoemulsification. When used herein, the term “dissipated energy” refers to the amount of energy, most commonly measured in joules, used by the handpiece during phacoemulsification. Lower dissipated energy readings mean that less heat is being produced during phacoemulsification, which in turn lowers the possibility of thermal damage to the delicate eye tissues. 
         [0011]    Use of an off-axis tip with a longitudinal hand piece appears to create a hybrid type of phacoemulsification motion without using the more complex and expensive torsional phacoemulsification apparatus. The inventors have also determined that the eccentric or wobble type of motion can be imparted to a phacoemulsification needle with no flare at the tip by forming the central aspiration passage within the needle body in an off-axis position. It is also expected that similar results will be obtained using a straight phacoemulsification needle having an aspiration passage that is formed with a cross-sectional configuration different than the cross-sectional configuration of the needle body itself, and that these results will be further amplified if the passage is also placed off-axis. 
         [0012]    Some interior surfaces of a needle tip may result in unwanted bounce-back or ejection of tissue particles from the opening of the aspiration passage in the needle body instead of being aspirated through the aspiration passage and transported through the needle body. Such bounce-back decreases the efficiency of the overall aspiration of the needle and may increase the time of surgery. The inventors have found that providing a controlled, sloping surface in the needle tip, which extends to the aspiration passage of the needle body, can improve the aspiration capability of the needle. Different sloping configurations disclosed herein may reduce and control the bounce-back or ejection of tissue particles. 
         [0013]    Furthermore, the inventors have found that texturizing both the needle tip surface and the surface of the sleeve can increase the surface area of the tip and sleeve surfaces to improve one or more of the efficiency of the surgery, aspiration time, and provide polishing of the capsule. 
         [0014]    While the following describes a preferred embodiment or embodiments 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 described and claimed herein. 
         [0015]    In accordance with one preferred embodiment of the present invention, a phacoemulsification needle is provided for emulsifying body tissue. The needle is adapted to be attached to a phacoemulsification handpiece imparting a vibration to the needle, The needle has body with a distal end, a proximal end, and an aspiration passage extending between the proximal and distal ends. The aspiration passage defines a longitudinally extending central body axis. The needle body has a mounting portion formed at the proximal end for mounting the needle body to a phacoemulsification handpiece. The aspiration passage is enlarged at the distal end to define a tip. The tip has a radially offset portion with an interior sloping surface that slopes radially inward in a direction along the body axis toward the body proximal end. 
         [0016]    In accordance with another preferred embodiment of the present invention, a phacoemulsification sleeve is provided. The sleeve is adapted to be attached to a phacoemulsification needle. The sleeve has a body with a distal end, a proximal end, and a through passage extending between the proximal and distal ends for receiving a needle. The sleeve body has at least one aperture for permitting flow of a fluid therethrough. The sleeve body has a textured exterior surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a side elevation view of a first embodiment of a phacoemulsification needle embodying the present invention; 
           [0018]      FIG. 2  is an enlarged view of the tip of the needle illustrated in  FIG. 1 ; 
           [0019]      FIG. 3  is an front elevation view of the needle tip illustrated in  FIG. 1 ; 
           [0020]      FIG. 4  is a cross-sectional view taken along plane  4 - 4  in  FIG. 3  of the needle illustrated in  FIG. 1 ; 
           [0021]      FIG. 5  is a cross-sectional view of a needle tip of a second embodiment of a phacoemulsifcation needle embodying the present invention; 
           [0022]      FIG. 8  is an front elevation view of a tip of a third embodiment of a phacoemulsifcation needle embodying the present invention; 
           [0023]      FIG. 7  is a cross-sectional view taken along plane  7 - 7  in  FIG. 6  of the third embodiment of a needle illustrated in  FIG. 6 ; 
           [0024]      FIG. 8  is a cross-sectional view of a fourth embodiment of a tip of a phacoemulsifcation needle embodying the present invention; 
           [0025]      FIG. 9  is a cross-sectional view of a fifth embodiment of a tip of a phacoemulsifcation needle embodying the present invention; 
           [0026]      FIG. 10  is a side elevation view of a sixth embodiment of a phacoemulsification needle embodying the present invention; 
           [0027]      FIG. 11  is a cross-sectional view of the needle illustrated in  FIG. 10 , the cross-section taken along a plane running through the body axis of the needle; 
           [0028]      FIG. 12  is a side elevation view of a seventh embodiment of a phacoemulsification needle embodying the present invention; 
           [0029]      FIG. 13  is a cross-sectional view of the needle illustrated in  FIG. 12 , the cross-section taken along a plane running through the body axis of the needle; 
           [0030]      FIG. 14  is an enlarged, perspective view of the tip of the needle illustrated in  FIG. 1 ; 
           [0031]      FIG. 15  is an enlarged detail view of the exterior surface of the needle tip illustrated in  FIG. 14 ; 
           [0032]      FIG. 16  is an enlarged detail view of the interior surface of the needle tip illustrated in  FIG. 14 ; 
           [0033]      FIG. 17  is a side elevation view of a phacoemulsification sleeve installed upon the distal end of the needle illustrated in  FIG. 1 ; and 
           [0034]      FIG. 18  is a simplified diagrammatic view of a phacoemulsification needle of  FIG. 1  connected to a vibratory handpiece. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0035]    Referring now to  FIG. 1 , the numeral  100  indicates a first preferred embodiment of a phacoemulsification needle embodying the present invention. Needle  100  is generally straight and has a needle body  104 . The body has an operative or distal end  99  and a proximal end  106 , defining a length of the needle body  104 . The needle distal end  99  has a tip  102 . The tip  102  preferably has a leading and trailing edge defined by an angle beta that is about  30  degrees to the plane running perpendicular to the length of the needle body  104 . The tip  102  need not be angled at all or may be defined by other angles.  FIG. 2  further illustrates that the exterior surface “A” of the needle tip  102  is preferably textured. The texture of the needle tip  102  will be discussed in detail hereinafter. 
         [0036]    Still referring to  FIG. 1 , the needle proximal end  106  may have a mounting portion or mating surfaces for connecting the needle  100  to a phacoemulsification handpiece (illustrated in  FIG. 18  only). The needle  100  may be connected to the handpiece in any manner such as by mating threads ;  clamping, friction fit, or adjustable fit. The needle body has an aspiration passage ( 124  in  FIG. 2 ) running from the proximal end  106  to the distal end  99  and defining a central needle axis  110 . As described hereinafter, directions inward or outward from the needle axis  110  are termed “radial” and directions along the axis  110  are either toward the distal end  99  or the proximal end  106 . 
         [0037]    Referring now to  FIG. 2 , which is an enlarged view of the needle tip  102 . The tip  102  can generally be characterized as having a flaring shape in which the aspiration passage  124  is radially widened at the needle body distal end  99  when compared to the radial height of the aspiration passage  124  in the remaining portion of the needle body  104 . The tip  102  may be characterized as having an open or hollow mouth  112  terminating in a lip  114 . As previously discussed, the tip  102  may have a leading edge  116  and a trailing edge  118 . The trailing edge  118  is preferably contiguous with the upper needle surface  120 , while the leading edge  116  is laterally offset from the lower needle surface  130 . However, in the broadest aspect of the invention, the tip  102  need not have any discernible leading or trailing edges, and the location of the leading and trailing edges may be positioned elsewhere along the lip  114 . 
         [0038]    Referring to  FIG. 3 , the tip  102  may have a central tip axis  126  that is offset from the needle body axis  110  by a distance  128 . The aspiration passage  124  can be seen to connect to lip  114  via the open mouth  112 . The first illustrated embodiment of the needle tip  102  can be seen to have a circular lip  114 . Orientation of the tip axis  126  to be offset from the body axis  110  may provide beneficial eccentric motion to the phacoemulsification needle distal end  99  during vibratory oscillation (longitudinal, torsional, or a blend thereof) by the handpiece (illustrated in  FIG. 18  only). 
         [0039]    Referring next to  FIG. 4 , which is a cross-sectional view taken along plane  4 - 4  of  FIG. 3 , the interior features of the needle distal end  99  and the needle tip  102  can be seen in detail. The first illustrated embodiment of the needle  100  shows that the tip  102  has an upper surface  103  that is coextensive with the upper surface of the aspiration passage in the needle body  104 . An offset portion  134  of the needle tip  102  can be seen to extend radially outwardly from body axis  110  further than the remaining portion of the tip  102 . A sloping surface  136  connects to an opening  140  of the aspiration passage that is coextensive with a lower surface  141  of the aspiration passage. The sloping surface  136  extends radially outward in the direction moving toward the open end of the tip  102  in a substantially straight surface defined by angle alpha. Angle alpha is the angle of sloping surface  136  with respect to the body axis  110 . Angle alpha is less than 90 degrees, and may be between 12 degrees to 90 degrees. Preferably the slope of surface  136 , or angle alpha, of is less than or equal to 45 degrees, The sloping surface  136  further connects to a second interior surface  137  at a point  138 , with second interior surface  137  being generally parallel to body axis  110 . Dimension “A” is the length, along the body axis  110 , of the second interior surface  137 . Dimension “B” is the length component, along the body axis  110 , of the sloping surface  136 , while dimension “C” is the height component of the sloping surface  136 . In the preferred embodiment, dimension “A” is greater than that of dimension “B”. Dimension “ 0 ” is the total height of the aspiration passage  124  at the needle distal end  99 . In the first illustrated preferred embodiment of the needle  100 , the tip  102  height “C” of the sloping surface  136  is at least one half of the total aspiration passage height “D”. 
         [0040]    The sloping surface  136  is preferably manufactured in a secondary step of milling the needle tip  102 . However, the sloping surface  136  may be created by other common manufacturing methods, such as being integrally formed in the needle body, or removed by etching, electrical discharge machining, or other material removal operations. 
         [0041]      FIG. 5  illustrates a second embodiment of a phacoemulsification needle  100 A that differs only from the first embodiment  100  in that the second embodiment  100 A has a sloping surface  136 A in the form of a curve, when viewed in cross-section. Sloping surface  136 A connects between the aspiration passage opening  140 A and the second interior surface  137 A. The curved sloping surface  136 A is defined by a radius “R” and forms a connoid shape in three dimensions, while forming a convex curve in two dimensions. The radius “R” of the sloping surface  136 A is preferably between 0.35 to 0.9 mm. This connoid shape of the sloping surface  136 A may reduce the amount of removed tissue material that is deflected from the sloping surface  136 A and thus improving the efficiency of the aspiration of the needle  100 A in needle where the body has a radially offset portion  134 A. 
         [0042]      FIG. 6  illustrates a third embodiment of a phacoemulsification needle  100 B that differs only from the second embodiment  100 A in that the third embodiment  100 B has a lip  114 B that is generally square in shape. Tip  102 B has a lip  114 B with two side edges  115 B, an upper edge  118 B, and a lower edge  116 B. As can be seen in  FIG. 7 , the third embodiment of the needle  110 B has a sloping surface  136 B in the form of a curve defined by a radius “R”. The radius “R” of the sloping surface  136 B is preferably between 0.35 to 0.9 mm. 
         [0043]      FIG. 8  illustrates a fourth embodiment of a phacoemulsification needle  1000  that differs only from the first embodiment  100  in that the fourth embodiment  1000  has an elongate radially offset portion  1340  defined by dimension “E”, generally along the needle body axis  1100 , The elongate offset portion of needle  100 C has a radially outward portion of the needle tip  1020  that begins to diverge radially away from the axis  110 C at a position axially inward of the at point  140 C. Preferably, the axial dimension “E” is greater than either of the axial dimensions “A” or “B” of the needle tip  1020 . The elongate radially offset portion  1340  of the needle  100 C increases the non-uniform distribution of the mass in the tip  102 C. It will be apparent that sloping surface  136 C may be straight or curved to form a connoid shape in three dimensions. 
         [0044]      FIG. 9  illustrates a fifth embodiment of a phacoemulsification needle  100 D that differs only from the first embodiment  100  in that the fifth embodiment of the needle  100 D has second radially offset portion  1500  opposing a first radially offset portion  138 D of the needle tip  102 D. Both first radially offset portion  138 D and second radially offset portion  150 D are offset radially outward of the body axis  110 D when compared to the remainder of the needle body  104 . The second radially offset portion  150 D of tip  102 D extends radially outward at a point  154 D of the aspiration passage  141 D. Point  154 D is axially inward, in the direction away from the open end of the tip  102 D, of point  1400  of the aspiration passage  141 D where the first radially offset portion  138 D extends radially outward from the needle body  104 . In the illustrated fifth embodiment of the needle  1000 , the second radially offset portion  150 D opposes the first radially offset portion  138 D, however in the broad aspects of the invention, the first and second radially offset portions need not be opposing and there may be more than just two radially offset portions in the needle distal end. Furthermore, the tip  102 D may have a generally circular cross-section, square cross-section, or other polygonal or irregular cross-section (not illustrated). The second radially offset portion  150 D of the needle  100 D may increase the non-uniform distribution of the mass in the tip  102 D and may improve aspiration by further widening the total surface area of the aspiration passage. 
         [0045]      FIGS. 10 and 11  illustrate a sixth embodiment of a phacoemulsification needle  200  that differs only from the first embodiment  100  in that the sixth embodiment  100  has an elongated offset tip  210 . Preferably the elongate tip  210  extends an axial length “A” that is at least one half of the axial length “B” of needle body  220 . Furthermore, the tip  200  may have a generally circular cross-section, square cross-section, or other polygonal or irregular cross-section (not illustrated). The elongate offset portion of the needle  200  increases the non-uniform distribution of the mass in the tip  210  and may improve aspiration by widening the area of the aspiration passage opening, 
         [0046]      FIGS. 12 and 13  illustrate a seventh embodiment of a phacoemulsification needle  200 A that differs only from the sixth embodiment  200  in that the seventh embodiment  200 A has an elongated offset tip  210 A with two portions offset radially outward of the needle body  220 A. Preferably the elongate tip  210 A extends an axial length “A” that is at least one half of the axial length “B” of needle body  220 A. Furthermore, the tip  200 A may have a generally circular cross-section, square cross-section, or other polygonal or irregular cross-section (not illustrated). The elongate radially offset portion of the needle  200 A increases the non-uniform distribution of the mass in the tip  210 A and may improve aspiration by widening the surface area of the aspiration passage opening. 
         [0047]      FIGS. 14, 15, and 16  contain detailed illustrations of the tip  102  of the first embodiment of the needle  100 . The safety and efficiency of phacoemulsification tips embodying the foregoing aspects of the inventive needles may be enhanced when the inner surface  152  and/or outer surface  154  of the phacoemulsification tip  102  are textured, as by tumbling, sandblasting, or other surface treatment method. Surfaces that have undergone this texturizing process appear to be pitted to create a much larger surface area for contact with tissue to be removed by phacoemulsification. The textured surface of the needle tip  102 , preferably on the order of between Ra 0.2 to 0.8., is believed to increase the efficiency of the aspiration process by disrupting adherence of the tissue to the needle tip  102 . 
         [0048]    Preferably, the lip  114  of the mouth  112  is polished to round the lip  114  and remove burrs which can damage delicate tissue in the eye, such as the posterior capsule, which may be contacted by the needle tip during the phacoemulsification operation. The lip  114  may be polished in another manufacturing process after the surface treatment of one or more of the interior and exterior surfaces  152  and  154 . Because of the relatively thin metallic material from which phacoemulsification needle tip  102  is formed, such edges that are not polished may be sharp enough to snag corneal tissue when a phacoemulsification needle is inserted through a corneal incision. Such edges may be sharp enough to damage delicate eye tissue, such as the posterior capsule, if the needle tip  102  is brought into contact with the capsule during surgery. The aforementioned polishing process of rounding and highly polishing and smoothing the lip  114  of phacoemulsification needle tip  102  of the type described herein reduces the likelihood that delicate eye tissue will be damaged during phacoemulsification, particularly if the needle is being used with a handpiece that produces torsional or elliptical motion. 
         [0049]    Referring next to  FIG. 18 , a diagrammatic view of the needle  100  is shown attached to a handpiece  250 . The handpiece  250  has a vibration imparting assembly  251 . The needle  100  is attached to the handpiece  250  at the proximal end  106  of the needle  100 . The handpiece  250  vibrates the needle proximal end  106  and causing the operative, distal end  99  to move at the surgical site. 
         [0050]    Referring finally to  FIG. 17 , an embodiment of an inventive phacoemulsification sleeve  300  for use with a needle  100  is illustrated. The sleeve  300  is hollow and has a proximal end  301  and a distal end  302  for being positioned proximal the distal end of the tip  102  (not visible in  FIG. 17 ) when the needle  100  is inserted into the sleeve  300 . The sleeve  300  may be made from any suitable elastomeric material such as silicone, rubber, or any hypoallergenic polymer. The sleeve has an exterior surface  303 , a portion of which may be textured by electrical discharge machining of a mold cavity from which the polymeric sleeve  300  is formed. Other surface treatments may be used, such as blasting, plastically deforming the sleeve  300  or molding a secondary material to the exterior surface  303 . The sleeve  300  has one or more apertures  304  for permitting fluid to flow from the interior of the sleeve  300  to the operative surface. Function of the sleeve  300  is in accordance with the operative principals disclosed in U.S. Pat. No. 7,601,135 B2. Surfaces that have undergone the texturizing process appear to be raised or pitted and may imbue the sleeve  300  with a polishing ability for polishing the capsule of the eye. The textured surface of the sleeve  300  may be on the order of 12 to 36 on the VDI scale, and is preferably about 24 on the VDI scale. 
         [0051]    It should be understood that although the embodiments shown depict specific wall configurations of the needle and needle tip, the invention should not be so limited. Selected walls or wall portions of the phacoemulsification needle can be manufactured to various thicknesses. 
         [0052]    The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.