referring now to fig1 , 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 . referring to fig1 , 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 . referring now to fig2 , 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 . both tips 10 and 18 in fig1 exemplify one form of a “ straight ” needle tip , that is , a tip that is coaxial with or centered on the hollow aspiration passageway formed through the needle body . other straight tips are known which have needle tips that are flared , that is , larger in cross - sectional area than the needle &# 39 ; s aspiration passageway yet which are centered on the passageway . referring now to fig3 , the numeral 40 indicates , generally , a phacoemulsification needle embodying certain aspects of the present invention . needle 40 has a hollow needle body 42 through which an aspiration passageway 44 is formed . needle 40 terminates at a tip 46 having a lip 48 which defines a tip mouth 50 . tip 46 is hollow having a tip cavity 52 which communicates with aspiration passageway 44 . as seen in fig4 , tip 46 is formed with an octagonal cross - sectional shape having outer tip wall segments 46 a , 46 b , 46 d , 46 e , 46 f , 46 g , and 46 h . as further seen in fig3 and 4 , tip 46 has a central axis 58 while a needle body 42 has a central axis 60 . in the embodiment shown , needle axis 58 is offset from tip body axis 60 by an offset distance 62 . offset 62 results from the fact that while a portion of tip 46 is coextensive with a portion of tip body 42 , other portions of tip 46 extend past tip body 42 . in other words , tip 46 is flared , meaning that a significant portion of the cross - sectional configuration of tip 46 is larger in diameter than that of needle body 42 and that the flare with which tip 46 is constructed is not symmetrical about needle body 42 . as seen in fig3 , tip wall segment 46 a has a first inner wall segment 64 which terminates at lip 48 and extends axially in a direction distal from lip 48 at an angle to tip wall segment 46 a . first inner wall segment 64 is contiguous with a second inner wall segment 66 which , in this embodiment extends generally parallel to and extending in a rear axial direction from first inner wall segment 64 . a third inner wall segment 68 is formed at an angle to second wall segment 66 and extends from second wall segment 62 to needle body 42 . in similar fashion , outer wall segment 70 of tip 46 extends at an angle to tip wall segment 46 a and terminates at and is integral with needle body 42 . thus , when tip wall segment 46 a , outer wall segment 70 and outer needle body wall segment 54 are contiguous as are inner first wall segment 64 , second wall segment 66 , third wall segment 68 and inner needle body 56 . as further seen in fig3 and 4 , outer tip wall segment 46 e which is diametrically opposite to wall segment 46 a is not offset from needle body 42 , with inner wall segment 72 of tip 46 being contiguous with inner wall 56 of needle body 42 . as can be appreciated from the drawings , wall segments 46 b , 46 c and 46 d are offset , to varying degrees , from needle body outer wall 54 . in like fashion , segments 46 f , 46 g and 46 h are similarly and varyingly offset . in a preferred embodiment , segment 46 e has little or no offset , segments 46 d and 46 f have identical offsets , being greater than the offset to segment 46 e , segments 46 c and 46 g have identical offsets , said offsets being greater than the offsets to segments 46 d and 46 f , segments 46 b and 46 h have identical offsets with said offsets being greater than the offsets of segments 46 c and 46 g , and 46 a has an offset greater than the offsets for segments 46 b and 46 h . as further seen in fig3 , the portion of tip 40 defined by segments 46 a , 70 , 64 , 66 and 68 include a greater amount of tip material than the portion defined by segment 46 e and inner surface 56 . in like fashion , varying amounts of tip material are contained in segments 46 b and 46 h , 46 c and 46 g , and 46 d and 46 f . this non - uniform distribution of tip material or tip mass makes tip 46 asymmetrical with respect to mass distribution as well as asymmetrical with respect to axis 60 of needle body 42 . referring now to fig5 , a phacoemulsification needle 74 is shown having a hollow needle body 76 through which an aspiration passageway 78 is formed . at the distal end of needle body 76 , a needle tip 80 is formed which , as seen in fig5 , is flared and has a larger cross - sectional area than needle body 76 . tip 80 terminates at a lip 82 which defines a tip mouth 84 . as seen in fig5 , tip body 76 has a central axis 86 while tip 80 has a central axis 88 with axes 86 and 88 being offset by a distance 90 . as seen in fig6 , tip 80 has a square cross - sectional shape having tip wall segments 92 , 94 , 96 and 98 terminating at and communicating with aspiration passageway 78 . as seen in fig6 , each tip wall segment has a corresponding inner wall portion with tip wall segment 92 having an inner wall portion 100 , tip wall segment having an inner wall portion 102 , tip wall segment 96 having an inner wall portion 104 , and tip wall portion 98 having an inner wall portion 106 . as seen in fig5 , inner wall portion 100 is formed at an angle to tip axis 88 . in like fashion , inner tip wall portions 102 and 106 are formed at angles to tip axis 88 and , in this embodiment , are formed at identical angles while inner wall portion 104 is formed at an angle to tip axis 88 that differs from the angles of inner wall portions 100 , 102 and 106 . as seen in fig5 , the angle at which inner wall portion 100 is inclined creates a tip body portion 108 differing in size and dimension than the tip wall portions defined by inner wall segments 102 , 104 and 106 . this configuration results in a non - uniform distribution of tip material which creates a “ wobble ” effect when needle 74 is vibrated by a phacoemulsification handpiece . as seen in fig3 - 6 , the needle embodiments described herein have outer tip wall surfaces which act as cutting or emulsifying surfaces when the tips are moved in a torsional direction . the non - uniform distribution of tip wall material adds to the efficiency of the tip when used in the torsional mode by adding increased torsional motion to the tip . referring now to fig7 , the numeral 110 identifies a needle tip having a generally octagonal configuration such as that shown in fig4 . tip 110 has flats 112 , with adjacent flats 112 meeting at apices 114 . an octagonal tip will have eight such flats and eight such apices . in the embodiment shown , an external ridge 116 is formed at each such apex 114 . as seen in fig8 , ridges 116 are formed integrally with tip 110 . it is also possible to form ridges 116 on tip 110 after tip 110 has been manufactured . as seen in fig7 , ridges 116 can be of varying lengths when tip 110 is formed with an angled or kellman configuration . thus , ridge 116 is longer than ridge 116 ′ which , in turn , is longer than ridge 116 ″ which , in turn , is longer than ridge 116 ′. while tip 110 is shown with an octagonal configuration , various other geometric shapes may also be used , with ridges formed and sized to fit at corresponding apices . referring now to fig9 and 10 , the numeral 118 identifies generally a needle tip having a generally octagonal shape . tip 118 has eight flats 120 , with adjacent flats meeting at apices 122 . as seen in fig9 , a series of blocks are formed on selected of flats 20 120 . in the embodiment shown , a first block 124 is formed on flat 120 ′, a second block 126 is formed on flat 120 ″, a third block 128 is formed on flat 120 ′″ and a fourth block 130 is formed on flat 120 ″. in this embodiment , none of flats 120 ′- 120 ′″ are adjacent to one another . each block is formed with a generally rectangular cross - section which rises above 25 its corresponding flat to a selected height and may extend a selected lateral distance between adjacent apices . as seen in fig1 , each block maybe tapered at its lead edge . thus , block 124 has a lead taper 132 and block 128 has a lead taper 134 . [ 0059 ] the blocks shown in fig9 and 10 are formed on non - adjacent flats : it is also possible to form blocks on selected flats depending upon the cross - sectional configuration 5 of the tip and the desired phaco effect . it is believed that configurations such as shown in fig7 - 10 benefit from having longitudinally - extending external ridges or blocks which have exposed lateral surfaces which , it is believed , increases phaco efficiency when the tip is moved torsionally .
a phacoemulsification needle has a polygonally - shaped tip with an axis that is offset from the axis of the needle body . the material forming the tip is non - uniformly distributed , adding to the motion of the tip when it is vibrated torsionally . in one embodiment , the tip has tip wall segments of varying thicknesses . in another embodiment , the tip has a series of external ribs formed on the tip wall segments , on the wall segment , at the apex where adjacent wall segments meet , or both .