Abstract:
An elongated, rigid cannula has a peripheral wall defining a central bore and a side port for introduction of material into the bore. A covering of resilient, flexible material is provided in the area of the side port, with a corresponding aperture aligned with the port of the cannula. The aperture of the resilient covering can be somewhat smaller than the underlying cannula port, forming a resilient margin that overhangs and surrounds the port.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Application No. 60/363,465, filed Mar. 11, 2002. 

   BACKGROUND OF THE INVENTION 
   Aspirators having small diameter distal tip portions are used during ophthalmic surgery, such as for removing cortical material, and cleaning and/or polishing the lens capsule, with or without simultaneous irrigation. During aspiration, the tip may engage fragile tissue of the lens capsule. The aspiration port of the tip can abrade or tear the capsule. 
   SUMMARY OF THE INVENTION 
   The present invention provides an improved aspirator tip having a rigid cannula wall with a side port for introduction of material into the bore of the cannula. A covering of resilient, flexible material is provided in the area of the side port, with a corresponding aperture aligned with the port of the cannula. In a preferred embodiment, the aperture of the resilient covering is somewhat smaller than the underlying cannula port, forming a resilient marginal portion that overhangs and surrounds the port. The resiliency of the covering around the port helps prevent abrading or tearing the lens capsule, permitting by deflection of the covering over the port, such as if the port is occluded. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a somewhat diagrammatic top perspective of an aspirator handpiece and tip component in accordance with the present invention, with parts shown in exploded relationship. 
       FIG. 2  is an enlarged, fragmentary top perspective of the distal end portion of the aspirator tip component of  FIG. 1 , with parts shown in exploded relationship, and 
       FIG. 3  is a corresponding enlarged, fragmentary top perspective with parts assembled. 
       FIG. 4  is a fragmentary side elevation of the distal end portion of the handpiece and tip component of  FIG. 1 , with the parts assembled and with parts shown in section, and 
       FIG. 5  is a further enlarged, fragmentary side elevation of the distal tip portion of the aspirator tip component, with parts shown in section. 
       FIG. 6  is an enlarged, fragmentary sectional view corresponding to  FIG. 5  but showing a second embodiment of the present invention; 
       FIG. 7  is a corresponding fragmentary section showing a third embodiment; 
       FIG. 8  is a corresponding fragmentary section showing a fourth embodiment; 
       FIG. 9  is a corresponding fragmentary section showing a fifth embodiment; 
       FIG. 10  is a corresponding fragmentary section showing a sixth embodiment; and 
       FIG. 11  is a corresponding fragmentary section showing a seventh embodiment. 
       FIG. 12  is an enlarged top perspective of the distal tip portion of another embodiment of aspirator tip component in accordance with the present invention, and 
       FIG. 13  is a corresponding enlarged fragmentary top perspective of a modified embodiment. 
   

   DETAILED DESCRIPTION 
   The present invention provides an improved aspirator tip component of the type inserted into a lens capsule, such as for removing cortical material, and cleaning and/or polishing. 
   With reference to  FIGS. 1-5 , an aspirator tip component  10  in accordance with the present invention includes a cannula  12  having a central bore  14  (FIGS.  4  and  5 ). The bore opens at the proximate end  16  of the tip component. The drawings are greatly enlarged in that the preferred embodiment of the aspirator tip component  10  will be sized for insertion through a narrow corneal slit during eye surgery. The proximate end  16  can connect to an aspiration handpiece  15  which, in turn, connects to a low pressure or vacuum source  18  indicated diagrammatically in FIG.  1 . 
   Typically the cannula  12  is formed of a rigid material such as stainless steel. In the embodiment of  FIGS. 1-5 , the distal end  20  can be hemispherical or otherwise blunted so as not to cut or puncture delicate tissue. Distal end  20  closes the bore  14 , and a side port  22  is provided communicating between the central bore  14  and the exterior of the cannula. The side port preferably is circular, but could be elongated in an alternative embodiment. 
   As best seen in  FIG. 2 , the diameter of the cannula  12  is reduced in the area of the side port  22 , providing a circumferential groove  24  which extends both proximally and distally beyond port  22 . Groove  24  terminates at an annular shoulder  26  at the proximate end and an annular shoulder  27  at the distal end. In this embodiment of the present invention, a covering in the form of a cylindrical sleeve  28  of resilient material such as silicone is fitted in the groove  24  of the cannula. The wall thickness of the cylindrical sleeve  28  preferably is essentially the same as the depth of the groove so that there is a smooth transition along the exterior of the cannula  12  and the exterior of the sleeve  28 . The proximate and distal ends of the sleeve  28  butt against or are closely adjacent to the annular shoulders of the groove. 
   Sleeve  28  has an aperture  30  which is aligned with but preferably smaller than the port  22  of the cannula  12 . This provides a marginal section that can deflect resiliently inward when aperture  30  is occluded. As compared to a rigid cannula, the soft covering is less likely to have burrs or rough edges which could tear delicate tissue, such as the posterior capsule. Similarly, if the instrument is brought into contact with delicate tissue, the deflection permitted around the port will lessen the possibility that a cut or tear will occur, even if there is limited movement of the tip after it contacts the tissue. 
   The sleeve  28  can be made translucent or clear so as to improve the visualization of material extraction, such as cortical material. The sleeve can be of sufficient resiliency as to be stretched over the end of the rigid cannula for installation, and can be secured in position by the resilient characteristics of the sleeve with or without adhesive or other manners of securing at the desired placement. 
   In each of the embodiments of  FIGS. 6-8 , the reduced diameter portion  24  of the cannula is continued to the distal end  20  of the instrument, eliminating the distal annular shoulder but leaving the proximate annular shoulder  26 . In the embodiment of  FIG. 6 , the sleeve  28  terminates at an abrupt, but soft, distal end  32 . In the embodiment of  FIG. 7 , the distal end portion  34  tapers into the rounded or blunt cannula end  20 . The sleeve also could extend almost precisely to the end  20 , or slightly therebeyond. In the embodiment of  FIG. 8 , the sleeve is of constant thickness, but with a closed, generally hemispherical end  36  that covers the distal blunt end  20  of the cannula. In each instance, the sleeve has the aperture  30  of smaller diameter than the cannula port  22 , such that a marginal portion of the resilient sleeve overhangs the inner port  22  and can be deflected. 
   In the embodiment of  FIG. 9 , the distal end  38  of the cannula  12  is open, with the sleeve being formed with a closed distal tip  40 , preferably rounded or blunt. Such a closed tip could be stiffer than the material surrounding the side aperture  30 . 
   With reference to  FIGS. 10 and 11 , another possibility is to provide the cannula  12  without a reduced diameter portion, but with the same larger diameter side port  22 . A resilient, flexible cover in the form of a sleeve is fitted over the instrument and has the smaller aperture  30  aligned with the cannula side port  22 . In that case, the distal end portion and/or proximate end portion of the sleeve cannula can be tapered toward the exterior of the cannula, as shown in broken lines in FIG.  10 . If the cannula is provided with an open end, a sleeve having a closed end or an end cap (like  FIG. 9 ) can be secured over the end of the cannula. In the embodiment of  FIG. 11 , the sleeve is identical to that shown in  FIG. 8 , the only difference being that the cannula  12  does not have a reduced diameter portion, such that the proximate end  42  of the sleeve is exposed. 
   The previously described embodiments use coverings in the form of sleeves with cylindrical portions, at least part of which would fit over a generally cylindrical cannula. With reference to  FIG. 12  another possibility is to use an inset piece  44  of resilient material in the area of the cannula or port  22 , rather than a continuous sleeve. The cannula  12  can be provided with a recessed portion around the port  22 , with the inset piece  44  closely received in the recess. The inset piece has the aperture  30  with a marginal portion overhanging the cannula port  22 . 
   The embodiment of  FIG. 13  is similar to the embodiment of  FIG. 12 , with the exception that the cannula  12  is formed with a longitudinally extending slot  46  in the area of a side port, with a handpiece inset piece  48  of resilient material fitted in the slot and having an aperture  30  of a smaller diameter than the cannula side port  22 . 
   While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.