CA2065386A1 - Removal of tissue - Google Patents

Abstract

To reduce damage to surrounding tissue while fragmenting some tissue, for example, not damaging the capsular wall while removing the lens during cataract removal surgery or not damaging artery or vein walls during bypass surgery while freeing the artery or vein to be transplanted, an incision is made for the insertion of a surface - discriminating, rotating, fragmenting tool (10) with blade portion (14). The blade portion (14) includes blades (17A and 17B) each of which is fastened to rotatable tubular shaft (18).
The tool (10) fragments and permits aspiration of the tissue without damaging the surrounding wall by fragmenting surfaces of higher inertia material but moving at a rate of speed and having openings between blades (17A and 17B) of such a size that the more integrated lower mass, more flexible and smoother tissue is moved away from the fragmenting zone and the higher mass, lower flexibility or rougher tissue is fragmented.

Description

20~386 :

~EMo~7Arl OF ~I~SUE

R~LATED CAS~ ~:
mhis application Is a continuat:ion-in-part of United States application 07/553,75 filed in the name of Aziz Y. Anis on Ju]y 17, 1990, for Pemoval ~
of ~issue. -BACKGROUND OF' q'HE INVENT10~
~ his invention relates to the remova] of tissue from the body such as for example remova~ of :,.
cataracts from the eye. .
It is known to remove diseased tissue from the body by fragmenting, crushing or otherwise making the tissue flowab].e while in the body and then aspirating it. In one known class of surgical techniques of this type specifically intended for the remova] of cataracts: (l) an incision is made along the superior corneal margin from about l0 to 2 o'clock (12 o'c~ock is the location closest to the top of the head of the patient) approximately l0 mm in chord length; ~2) an incision is made in the capsular wall; and (3) the cataract is removed. The ~nterior chamber is maintained substantia1]y formed ',;

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during the operation by means of a continuous inflow of irrigating solution.
In one prior a~t technique of this class for removing a cataract, the nucleus i.s expressed out of the eye and the cortex i5 removed by a process of irrigation and aspiration. In anot:her prior art technique of this class for removing the cataract, the nucleus is removed with a vectis and about O.l milliliter of viscoelastic compound or ir~igating flui~ is introduced into the capsu]ar bag to separate the capsu]ar wal].s. With the capsu1ar wa].ls separated, a wedge of the cortex is enga~ed in the aspiration port of a cannu]a and peeled toward the center and then aspirated to remove ~t. ~his process is repeated so that the .1.ayers of the cortex are peeled and then aspirated inwardly through the cannula, ~.ayer by layer! unti.l the intact capsu].ar bag (except for the horizonta.1. incision) is completely empty and clean.
This technique of removlng the cataract is disclosed by Anis, Aziz Y., "I1l.ustrated Step by-Step Description of the Anis Dry Extra Capsular Cataract Extraction ~echnique With In-the-~ag Lens Implementation"; Seminars in OE___Imo~ogy, v~ l, ~.

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W O 92/01423 P(~r/US91/04959 3 2~53~6 2 (June) 1986 pp. 113-129 and the technique is com~ared with other such techniques o~ this c]ass.
Two prior art types of instruments which aid in the fragmentation and aspiration of t~e lens nuc~eus to permit extraction through a sma].l incision are disc]osed in Unlted States patent 39589 36~ to Anton Panko et al.; United States patent 3 902 495 to Steven ~7. ~eiss; United States patent 3 6~3 613 to Charles Kelman et al.; and Uni~ed States patent 4 Oal 947 to Steven N. Weiss et al. ~his instrument is intended in the prior art to fragment a lens nucleus using uJtrasonic vibrations to aid the irrigation/aspiration of the lens. The ultrasonic vibrations laterally reciprocate the tip of an instrument to fracture the cataract a~ter which it can be aspirated.
A further type of instrument is discJosed in United States patent 4 908 015 issued to Anis on ~arch 13 1990. This~patent descri.bes an instrument which rotates a solid member having b1.ades extending from it to grind the lens.
These tissue remova] techniques have severa~
disadvantages such as: (1) they risk tearing the capsular wa~J with the reciprocating U7 trasonic vibration tools or with the rotating bJades; (2) .", ~ ' ~

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WO92/01423 PCT/US91/0~959 3 ~ ~

under some circumstances, thev require ]arge incisions in or removal of parts of the capsu~ar wall; and (~) they may require the use of severa]
different instruments.
Sti~l another type of prior art technique for removing cataracts is disclosed in United States patent 3,996,935 to Banko issued December 14, 197h.
~his type of instrument shows cooperating jaw-~ike members, one of which rotates inside the other to break up the lens by shearing sections o~ it. It aspirates fragments through the instrument. ~his type of instrument has a disadvantage in that it can break the capsular wall and is relative~y complex.
Part of the disadvantage comes from the teaching that it may be rotated manually or mechanicall.v without a corresponding teaching of the rate of rotation required for efficient use.
Still another prior art instrument includes a sma].l rotary magnetic cutter that is injected throuyh the capsu]ar wal~ and a means for applying magnetic fields that control the magnetic cutter in position. ?he small magnetic cutter is rotated as lt moves from position to position in the capsu~ar bag and to abrade or cut the lens that is to be removed.

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WO92/01423 PCT~I]S91/04959 ' 2 (~ 3 g ~
' This instrument has several disadvantages, such as: (l) it is re].atively complicated an~ expensive .
because of the nee~ to remotely control the smal] ;
c~tter; and (2) does not incorporate any mechanism for aspirating the lens particles as they are abraded from the lens.
In still another prior art device disclosed in :.
U.S. patent 4~OO2t169J small retractable wires are .
rotated in a range of 5 rpm to 16,000 rpm. There is .
no teaching of selecting the speed for surface ~
discrimination and the device relies on b~unt :' surfaces to avoid damage to the capsular walJ. .
instead. This device has the disadvantages of: (l) providing a relatively slow cutting velocity range with blades not shaped for cavitation or turbulance; ;
(2) not providing a range of ve~ocities sufficient .~ .
to form small particles that can be aspirated ' through a sma~l hole; and (3~ not providing for .~;
aspiration during fracgmenting, thus blocking ~:
visibility with particles. .:

SUMMARY OF THE INVEN~ION :
Accordingly, it is an object of the invention ~ .
to provide a novel technique for tissue remova.l.

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It is a further object of the invention to provide a novel instrument for fragmenting and removing a cataract during cataract removal surgery with ]ow risk of damage to the capsular wall.
It is a sti~l further object of the invention to provide a novel instrument designed to fragment tissue witho~t damage to the nearby tissue such as for example not damaging the capsular wall while removing the lens during cataract removal surgery or not damaging artery or vein walls while removi~g cancerous tissue near the vein or artery. -It is a still further object of the invention to provide a novel technique for fragmentiny and removing a cataract in which technique a moving fragmenting surface moves at an angle with the normal to a cataract surface, which angle is obtuse and generally close to heing perpendicular to the normal in such a manner as to cause cavitation at -its trailing edge to aid in fragmenting and mixing the cataract particles while maintaining the direct force on the cataract relatively low.
In accordance with the above and further objects of the invention, an incision is made for ; ;the insertion of a surface-discriminating fragmenting tool. The surface-discriminating : .
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2 ~ 6 fragmenting tool fragments and permits aspiration of high mass, rough-surface, rigi~ tissue without damaging nearby smooth, flexible, .~ow mass walls.
The tool fragments some tissue but avolds fragmenting other tissue by discriminating between tissues. This discrimination is based on one or more of several factors including: (l) the rigidity of the tissue; (2) the amount of mass of the tissue;
(3) the angle of the tissue to the direction of movement of the tool; (4) the roughness of the surface of the tissue; and (5) the size and shape of the surface of the tissue to the extent the size and shape affect the tendency of ~he negative pressure created by aspiration and/or irrigation to move the tissue toward the surface-discriminating fragmenting tool.
The surface disc.rimination of the tool is control~ed by moving surfaces which fragment diseased tissue on impact, referred to as phacotmesis, and cause cavitation forces that further fragment and mix fragments of tissue, referred to as phacocoelosis, but which move at a rate of speed slow enough so that the more integrated, more f~exible, lower mass and smoother tissue is moved away without fragmenting. The .. . . .. :, , , . . . - : : .

W O 92/01423 PC~r/US91/04959 ~l)6~6 tissue is not constrained by opposed shear forces of the tool as in some prior art rotating tools nor is the higher mass, rigid tissue moved significantly as a bu]k.
The surfaces of the instrument fragment tissue that: (1) is stiffer and has a higher modulus o~
rigidity; and (2) is at an angle to the cutting edge closer to 90 degrees and receives ]ess force moving it away. Thus, the surgeon removing a cataract adjusts the speed of movement of the tool surfaces aspirating and irrigation forces, rake angle of the leading edge and cavitation level as controlled by ;
position of tool surface, velocity and shape of moving surface, especially the trailing edge. The adjustment is made to fragment the cortex because of its higher mass, modulus of elasticity and projections in the path of the tool surfaces bu~ to move the capsular wall because of its ]ower mass, lower modulus and fewer pro~ections closer to 90 degrees and not fragment it.
The aspiration pressure is more effective within the moving surfaces of the rotating tip. It is low enough to pull the fragmented tissue an~
tissue to be fragmented but does not hold the smooth flexible capsular wall against movement away from ' . ..'' ., ' .

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the moving sur~aces of the tool. The rotating surfaces move the smooth wall o~tward]y and provide ~
some counter pressure to the aspirating pressure inside t~e fragmenting zone. In one embodiment, radia~ly inwardly extending edges further pull and mix tissue within the fragmenting zon~e. .
In the case of cataract removal surgery, a ;~
small incision of 2 to 7 millimeters and preferably 3 millimeters is made in the sclera along the .:::
corneal border at 12 o'c~ock and another incislon of similar dimension or a round hole in the anterior capsular wal].. The i.nstrument is inserted and fragments the lens matter without fragmenting the capsu~ar wall.
In the preferred embodiment, the surface-discriminating, fragmenting handpiece includes a shaft with an aspirating port in it within one or more rotating rings or loops or curved sections.of a cylinder. The rotation is at a sufficient speed and the area o the open spaces between the fragmenting edges sufficiently small so that relative]y smooth intact, flexible, low-inertia tissue such as the capsular wall does not remain in the path of the fragme:nting surfaces because the fragmenting surfaces move it away and close the opening leading : ' ::
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to the fragmenting zone with great frequency during the rotation while permitting the rougher or higher mass, more rigid portions of the lens to be fragmented.
The factors useful in surface-discriminatory fragmenting differ from eye to eye or tissue to tissue and may be selected in accordance with the surgeon's observations. These factors are the speed of the moving surfaces with respect to the tissue, the holding pressure from aspirating vacuum and irrigating liquid, the location and position of the moving surfaces, the rake angle of the cutting edge of the moving surfaces and the shape of the portions of the moving surfaces most related to cavitation.
These factors are established by the surgeon as a function of the mass of the capsular wall and the mass of the tissue to be fragmented, the stiffness and smoothness of the capsular wall or other healthy smooth tissue and the hardness and flexibility of the tissue.
The moving surfaces of the fragmenting tool hit the cells at a substantially tangential ang~e and distort them or cut them with their leading edges , while the trai~ing edges create cavitation that further breaks and mixes the tissue without ~ ~:

WO92/01423 PCT/U~91/04959 2~6~38~

imparting suc~ force to the tissue in a direction that may injure the capsular wall. For large and rigid or for rough surfaces, the shear force and cavitation is suf~icient for fragmentation whereas for more flexible, lower mass and smoother surfaces, the leading edges and the cavitation tend to move the surface away and thus avoid fragmentation. The aspirating port or ports tend to pul] the fragmented material internal to the tool.
In a preferred embodiment, a tubular member has a central aspirating channel along its longitudinal axis with one end having a fragmenting tip and the other end being adapted to rotate the tube. The fragmenting tip has at least one slotted fragmenting surface, with the slot extending substantially in a direction parallel to the longitudinal axis of the tube for at least a short distance. The sections between slots at the end of the tube may be bent inwardly to provide a blunt top surface or offset to form a top drill bit. The longi~udinal leading edge of the slots are positioned to establish a rake angle and the surfaces may be shaped to provide a fluid pressure inwardly or outwardly to create more or less cavitation so that a tip can be selected by the surgeon in ac~crdance with his needs.

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WO 92/01423 PCl`/U!~igl/04959 To provide the desired cavitation, there is a blunt trailing edge shaped to increase cavitation.
The ]eading edge offers less resistance to the lens matter and any visco~s fluid in the eye or other fluid thro~gh which it moves than the trailing edge, the trailing edge being adapte~ to increase cavitation while the leading edge compresses, distorts and cuts the tissue that is to be removed.
In one embodiment, the blunt end faces slightly outwardly from the circle of revolution of the tube to create maximum cavitation outside the shell of the tube rather than inside. The leading edge may be at an angle to provide sharpness and the adjacent wall may extend outwardly to create inward flow and hold tissue and draw tissue inwardly in cooperation with ~he aspirating negative pressure.
~he diameter of the tube and the number o' -~;
slots are selected to provide the selected amount of cavitation and cutting. The width of the slots is selected to avoid the movement of the more flexible tissue that is not to be fragmented in front the ]eading edge but short enough so that the heavier mass, rougher surfaced and/or more rigi~ material to be fragmented does not move away because of its inertia daring the rotating. In one preferred ,''' "' ',~
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embodiment,.the cavitation is at 1ow frequency be].ow the ~ltrasonic frequency range.
As can he und er stood from the above description, the technique and instrument of this invention have several. advantages, such as: (1) they selectively fragment some tissue without damaging other nearby tissue; and (2) they are able to fragment, mix and aspirate tissue and in the case of cataract removal, also scrub the capsul.ar wall without damaging it. .
~ ' ~
SUMMAP.Y OF THE n~AwINGs The above noted and other features of the invention will be better understood from the ~
following detailed description when considered with .2ference to the accompanying drawingst i.n which: :~
FIG. 1 is a simplified elevational view of a handpiece an~ control console for fragmen~ing and removing cataracts in accordance with an embodiment of the invention;
FIG. 2 is an enlarged perspective view of a -portion of the embodiment of FIG. l; ;
FIG. 3 is a fragmentary sectional view of :
another portion of the embodiment of FIGo 1, : , ':

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WO92/01423 PCT/US9~/04959 20~5~86 FIG. 4 is a fragmentary perspective view of another embodiment of blade portion usable as a replacement for the blade portion in the embodiment of FIG. l;
~ IG. 5 is a plan view of the embodiment of FIG.
4; .
FIG. 6 is a fragmentary elevational view, partly sectioned and partly diagramatic of another embodiment of handpiece;
FIG. 7 is a fragmentary elevational view of another embodiment of tool portion;
FIG. 8 is a top view of the embodiment of FIG.
7;
FIG. 9 is an elevational righ~ hand view of the embodiment of FIG. 7; ~;
FIG. 10 is a fragmentary elevational view of a tool tip which represents a variation of the tool tip of FIGS. 7-9;
FIG. ll is a diagramatic top view of a tool tip illustrating a first step useful in making the embodiment of FIGS. 7-9;
FIG. 12 is a fragmentary elevational view of the tool ~ip shown in FIG. 11;

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WO92/01423 PCT/USg1/04959 2 ~ 6 ~ ~ 8 6 FIG. 13 is an elevational view of a tool tip illustrating a second step in preparing the embodiment of FIGS. 7-9;
FIG. 14 is a top view of the tool tip shown in FIG. 13;
FIG. 15 is a fragmentary perspective view illustrating an additional step in preparing the embodiment of FIGS. 7-9;
FIG. 16 is a perspective view illustrating stil] another possible step in preparing a tool tip similar to the embodiment of FIGS. 7-9;
FIG. 17 is a block diagram of a process for using the instrument o~ F~GS. 1 through 6 to remove a cataract; and FIG. 18 is a simplified cross-sectional view of an eye and cataract removal handpiece tip illustrating a portion of the technique of this invention.

DETAILED DESCRIPTION
In FIG. 1, there is shown an e~evational view of a sur~ace-discriminating fragmenting handpiece ~lQ, connecting tubing 23 and a console 21. The handpiece 10 includes a drive portion 11 and a surface discriminating fragmenting tool haviny a , . . ~ . . : , . . , , . . ,,, . . . - .

2 0 ~ 6 h~ade portion 14 and a tubular s~eeve portion 12.
The tubular s~eeve portion 12 includes a tubu1ar casing 13, and an inner tabular aspirating drive shaft or s~eeve 18. ~he drive portion 1] houses the motor, an on-off switch 20 and connectors for irrigating fluid and aspirating vacuum pressure.
The blade portion 14 includes blades 17A and 17B each of which is fastened to the rotatab'e tubular shaft 18 at diametrically opposite locations on the shaft and each of which has a corresponding one of the blunt tips 15A and 15B turned inwardly to avoid cutting. The outer sleeve 13 includes within it a movable sleeve 19~ so that upon longitudinal movement of the button 19 with respect to the outer casing 13 of the tubular sleeve portion 12, the blades 17A and 17B m~ve apart in a fragmenting posi~ion in response to one direc.ion of movemen~ of the shaft 19A and are forced within the movable sleeve l9A within the tubular sleeve 12 against the pressure of the spring-like blades upon movement in the other direction to fit within a smaller incision such as a 2 millimeter opening. The blades 17~ and 17B are narrower in the direction of rotation and blunt on the trailing edge to cause cavitation.

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WO92~01423 PCr/US91/04959 17 2~386 With this arrangement the blades 17A an~ 17 may be moved toge~her for insertion of the handpiece 10 into the capsu1ar sack through a relative].y small aperture and then permitted to expand outwardly so that the upon rotation of the blade portion 14 of the tool section the cortex and nuc~eus are fragmented within the capsular sack. In the embodiment of FIG. 1 the handpiece 10 includes a motor for rotating the shaft and a tubular connector 23 for aspirating fragments. The conso~e 21 may include for cooperation with the handpiece 10 a standard source of electrica] power~ a vacuum source a source of irrigating liquid and a pump for .irrigating liquid. These elements are conventional and are not part of the invention except insofar as they cooperate with the handpiece 10.
In FIG. 2 there ~ 5 shown an enlarged fragmentary perspective view of the ~lade portion 14 of the tool assembly having first and second blades 17A and 17B with corresponding bl.unt ends 15A and 15B. The blades 17A and 17B are sufficiently flexible in the embodiment of FIG. 2 to expand until they form outwardly curved cutting surfaces extending beyond the surfaces of shaf~ 13 ~FIG. 13 and have sharpened edges ~2 and 34 tangentia].ly to 2 ~

or pointing inwardly from the circles o~ rotation formed as they rotate. ~hen the b]ades 17A and 17B
.
are pulled inwardly by movement of the sleeve l9A
upwardlyr they fit within a cylinder having a diameter of less than 2 millimeters.
While the embodiment of FIGS. 1 and 2 have blades with sharpened edges pointing tangentially to or inwardly from the direction of rotation, sharpened edges are not necessary and the angle of attack or rake angle of the sharpened edges when they are part of an embodiment may vary. However, the angle of attack may be tangential to the path of rotation or any angle on either side. For this purpose, any one of several multiple blade assemblies 1~ with their attached inner drive shaft i8 ~nay be inserted into the sleeve por~ion 12 and drive portior: 11. The blade portion is selected by the physician and one fact in such se]ection is the angle of attack of the blades.

~ o permit compressing of the blades 17A and 17B
into a protective sleeve, the tubular sleeve portion 12 includes three coaxial s.leeves 18, l~A and 13 (FIG. 1) in that order outwardly from the central axis. The blades are mounted to tubu]ar drive sleeve 18 for rotation therewith and there is a :. :
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WO92/01423 PC~/US91/04959 2~53~6 space between sleeves 18 an2 l9A for irrigating fluid ~o flow. The sleeve l9A is a~fixed to the button 19 (FIG. 1) and moveab.le axial].y with respect to sleeve 13 to engage the blades 17A and 17~ and compress them inwardly.
In FIG. 3, there is shown a fragmentary .
longitudinal sectional view of the sleeve portion 12 and drive portion 11: (1) having within the sleeve portion 12 the rotatab].e tubular aspiratina drive shaft 18, the tubular protective sleeve 19~ and the outer sleeve 13; and (2) having within the dri~e portion 11, a motor 40 for rotating the aspirating drive shaft 18 to turn the blades 17A and 17~, (FIG.
1) a hollow aspirating tube 27 to apply vacuum pressure to the interior of the shaft 18, an irrigating tube 17 communicating with the tube l9A
to apply irrigating fluid through the tube l~A and electrical wires 25 to control the motor 40. The shaft 18 is coupled at one end 42 to the output shaft of 4q of the motor 40 for rotation therewith . :-and to the tubular connection 45 for aspiration.
As shown in this view, the outer wall 13 supports~within it a movable wall l9A wlth a button extending through a slot in the outer wa].l 13 by which the wall :L9A may be moved upwardJy and . "
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downwardly to bend the blades 17A and 178 inwardly for retraction or permit them ~o expand outward]y in the cutting position to their normal position for .
rotating and in some embodiments still further unde~
centifugal force when rotating. However, the moment of inertia of the blades is sufficient so that the centrifugal force does not force the points to point outwardly and only the bent flat surface is presented to the outer wall during rotation. It is spaced from the movable tube l9A to permit irrigating fluid to flow therebetween and contains in its center the opening 15 which extends downwardly for aspiration of tissues. `~
~o pravide irrigating f~ui.ds, the conduit 17 is connected through the cable 23 to the console 21 .
(FIG. 1) from which irrigating liquid is pumped through the conduit 17 around the motor 40 and to the space between the movab].e tube 19 and shaft l8 "
to supply irrigating fluid to the capsular sack. To aspirate tissue, the central opening 15 in the shaft 18 passes through an opening 29 in the wall of the shaft 18 and communicates through the sealed circular ring ~1 with the aspira~ing conduit 25. :
The conduit 25 passes around the motor 40 and through the cable 23 to the console 21 which applies "-:

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W092/0l423 PCT/US91/04959 20653~

slight negative press~re to asp~rate tissue. The cable 23 also carries electrical conductors for the motor 40 which are connec~ed in series between the switch 20, and a so~rce of electrical power in the conso]e 21 and the motor 40.
To use the embodiment of FIGS. 1-3, an incision is made for the insertion of the surface-discriminating fragmenting handpiece lO. The surface-discriminating fragmenting handpiece lO
fragments and permits aspiration of the tissue but avoids damaging nearby smooth, flexible walls.
Instead it fragments rougher, more rigid surfaces of higher masses. ~his surface discrimination is controlled by the moving surface of the blades 17A
and 17B which permit the diseased tissue to be strained or cut by the blades and further fragmented by the forces of cavitation within their fragmenting zone but which move at a rate of speed and have openings between them of such a size that the more integrated, lower mass or more flexib]e and smoother tissue does not fall within their fragmenting zone but is moved away the moving surfaces. The aspirating pressure, cavitation and turbu]ence is coanteraoted or attenuated within the sphere oE the ': , ' ::

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20~386 rotating ring to avoid damage to the ~lat surface tissue.
In the case of cataract removal surgery, a small incision of 2 to 7 mil]imeters and preferab1y 3 millimeters in the schlera along the corneal border at 12 o'clock and another incision of similar , . - .... ..
dimensions in the capsular wall. The instrument is inserted and fragments the higher mass, more rigid, rougher lens without fragmenting the capsular wall.
The actual time that the fragmenting zone must be open to fragment diseased tissue without injuring smooth walls differs from eye to eye or tissue to tissue and may be selected in accordance with the surgeon's observations prior to use. It is a function of: (1) the rigidity of the tissue; (2) the mass of the tissue; ~3) the angle of the tissue to the direction of movement of the tool; (4) the ~ :~
roughness of the surface; and (5) the effect of the negative pressure pulling the tissue inwardly such as the aspiration vacuum pressure which may vary in its effect depending on the size and shape of the tissue. , The surface discrimination of ~he tool is controlled by moving sur~aces which cause the ;. .
diseased tissue to fragment under impact, referred - .

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2 D S !~ 3 ~ 6 to as phacotmesis, and cavitation forces, re~erred to as phacocoe~.osls, but which move at a rate o~
speed slow enough so that the more integrated, more flexible, lower mass and smoother t.issue is moved away without fragmenting. The surfaces of the instrument fragment tissue that: (l) is sti~f; (2) has a high mass and large inertia; and (3) is at an ang]e to the cutting edge c]ose to 90 degrees.
~ o take advantage of the differences between the tissue to be fragmented and the lower, more flexible tissue, the surgeon removing a cataract adjusts the speed of movement of the tool surfaces, the aspirating and irrigation rates, the rake angle of the leading edge of the b].ade surfaces and the cavitation level as controlled by position of blade surfaces, the velocity and the shape of the moving surface, especially the trailing edge of the blades.
~he adjustment is made to fragment the cortex because of its higher mass, modulus of elasticity and projections in the path of the tool surfaces but to move the capsu.lar wall away from the blades because of its lower mass, lower modu].us and fewer projections closer to 90 degrees. Tips are rep].aced to change the rake angle and cavitation surfaces.

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The aspiration pressure is more effective within the moving surfaces of the rotating tip. It is low enough to puIl the fragmented tissue and tissue to be fragmented but does not hold the smooth wall against movement nor pull it inwardly. The rotating surfaces move the smooth wall outwardly and provide some counter pressure to the aspirating pressure inside the fragmenting zone. In one embodiment, radially inwardly extending edges further pul] and mix tissue within the fragmenting zone.
To better describe this and other em~odiments, some special terminology is useful. For purposes of this description, the words, "low power" means less than one horsepower (1.341 kilowatts~. In this description, the words, "motion resistance" means the resistance of a portion of tissue to movement when impacted by a moving tool surface caused by the inertia of the tissue an2 the ef~ect of the inertia of other tissue connected to it taking into consideration the flexibility of the connecting tissue.
In this description, the words, "fragmenting velocity", means the minimum ve~ocity of a moving surf~ce o~ a tool with respect to predetermined . ~

, WO92/01423 PCT/US9]/049~9 2~6S3~g . ' stationary tissue that the moving surface of the tool impacts which fragmenting ve~ocity is sufficient to cause strain in the tiSc;ue of at least ten percent of the distance moved by the entire tissue mass and to break the tissue by combined strain, cutting and cavitation effects when: (1) the predetermined stationary tissue has a predeter~ined motion resistance; and (2) the tool surface has sufficient kinetic energy to maintain its vel.ocity constant in spite of the impact. The fragmenting velocity is affected by: (1) the angle the motion of the moving surface makes with the surface of the ;.
tissue; and (2) the momentum of the moving surface.
In the embodiments of FIGS. 1-3, a ring or partial ring having a diameter of 2 mil]imeters in the widest distance perpendicular to the axis of revolution forms a s~rface of revolution when rotated having at any one time open spaces and a solid cutting ring. The ring is rotated at approximately 120,000 rpm (revolutions per minute). :
The solid ring is approximately 0.50 millimeter wide .: .
a.long the surface oP revolution, leaving an open area in the surface of s~ightly less than 9 square : ~illimeters and more precisely a7g square : .
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mil]imeters with a length of 2.4 mi~limeters at the longest circle of a segment.
The time between portions of the solid ring sweeping across any surface of revolution is approximately every 250 microseconds and should be no longer than once every 3 milliseconds tl,000 rpm) but may be as short as 0.75 microsecond ~400,000 rpm). With this arrangement and with parameters adjustable for the particular circumstance~ the capsular wall does not enter into the fragmenting zone within and near the surface of revolution and is not cut and yet the ring is able to fragment the lens for easy aspiration.
In FIG. 4, there is shown a second embodiment of blade portion 14A having a shaft 18A connected to a b~ade 17C formed as a partial zone of a circle or an arc extending from the shaft 18A and having a pear-shaped, blade portion with: (1) blunt trailing edges 20; (2) sharpened inner edges 22; (3) a wide base attached to the shaft and narrower along the axls of the tube 18A so that there is at the wide portion a blunt trail.ing edge and a sharpened leading edge as the cutting blade rotates about the ; shaft 18A; and (4) an axis of rotation along the shaft 18A between the base and the narrower upper ~

, " " :, , ~ : : : . , ,, . ~ , ". .':: ' , . , , ' ' ' ,: , . . ' ' " " : ' ' ' ~ ', ,.,; '`' '` .' , ` ' '" ' " '' ' ,' ' , ' . " ' ' .. ':' WO~2/01423 PCT/US91/04~59 27 2~5~6 portion. The apex is generally blunt, but in some embodiments has a drill shape at the apex 24.
It has been found that the sharpened edges strain and elongate the cells of higher mass rigid material but push away flexible and low mass material. The leading edges under some circumstances cut or scrape fine particles from the harder material that might otherwise plug the aspirating channel but the cavitation effect fragments the particle-s into smal~ particles that can easily be aspirated. ~he blades are shaped to maximize cavitation that ]i~uifies and stresses ]ens matter and any viscous fluids and causes fragmentation and mixing of the higher-mass more rigid material. In the embodiment of FIG. 4, the blades have two blunt sides and a top blunt portion 24 and at the mounting base to the tube l~A for strength at the bottom and to form a non cutting surface at the top.
In FIG. 5, there is shown a top view o~ the em~odiment of FIG. 4, having a portion l~A with a blade 20B shaped with a thicker portion having a blunting surface 24 at its upper end facing away from the direction of the tubular shaft 18A and rotating thereaboutO ~owever; in some embodiments ~ ' ~,,. '.

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it has a cutting edge to permit it to provide an abrading center area in the forward direction for positioning at a point to be fragmented. This embodiment operates substantial]y the same as the prior embodime~ts except that its unique shape enables careful p]acement for special purposes.
Instead of a cutting edge, the top portion 24 may be bent inwardly or may be b]unt to avoid cutting at its top.
In FIG. 6, there is shown a fragmentary, partly diagramatic and partly longitudinally sectioned view of another embodiment of hand tool lOA whic~ is operated by a simi~ar dental drill motor 40 and adapted to receive a tool by having inserte~ therein the aspirating tube 18B of the sleeve portion 12~
substantially identically to that of the embodiments of FIGS. 1-5 except that the b]ade portion is constructed in a different manner on the end of the shaft 18 as will be descr:ibed hereinafter.
The hand piece lOA includes in addition to the aforementioned motor ~0, an aspirating drive sleeve 18B, an outer housing 60 and a motor-tool sleeve coupling 62 with: (1) the motor 40 being connected to the too~ sleeve 18B through the coupling 62 and being located within the housing 60; (23 with the .-: . .

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sleeve 18B extending ou~wardly thereof for rotation by the motor 40 through the coupl.ing 62 during operation of the hand piece.
To enclose and provide the necessary liquid and vacuum connections to the operative tool, the housing 60 inc]udes a motor housing portion 70 and a tool and coup]ing housing portion 72 intergrally formed together with tubular connectors 74 for irrigating fluid, tubular connector 76 for aspirating ne~ative pressure and hole. 78 for air venting being provided through the housing 60. The air vent port 78 is an opening extending into and communicating with the interior of the motor housing portion 70 to provide cooling to the motor 40. The irrigating fluid connector is an opening communicating with the interior of the housing portion 72 to apply fluid therethrough ~or eventual passage through the protective sleeve 13A on the outside of the tooling s~eeve 18B and to the operating point in a manner to be described more fully hereinafter.
The aspirating connecting opening 76 is adapted to receive tubing for applying negative pressure through the motor-tool coupling 62 to the interior . ~:
::; of the tooling shaft 18B to withdra~ material during ..

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WO~2/01423 PCT/US91/04959 2 ~ 6 ~i r~ ~ ~i 30 use of the hand piece. The forward end of the housing portion 72 includes external threads 82 which engage internal teeth on the protective sleeve 13A and a shou]der with an O-ring 80 positioned in it so that, the protective sleeve 13A can be threaded onto the housing 60 to enclose a portion of it sealinglv and extend through its outer end in a manner to be described hereinafter.
~ o connect the motor 40 to the sleeve portion 12B, the motor-tool sleeve coupling 62 includes the motor output shaft 90, a cylindrical boss 92, a cylindrical support member 94, an annular groove 96 within the boss 92, two counter bores 98 through the boss 92 at the bottorn of the annular groove 96, an opening 100 communicating with the aspirating connector 96 and extending through the cylindrical support 94, a cylindrical opening 95 sized to receive the sleeve 18B and a brazed connection 102 more firmly fastening the boss g2 to the sleeve 18B.
~he support 100 receives the motor shaft 90 and the boss 92 which rotate within it and are supported by it. The groove 96 cornmun.icates with the opening lV0 as it rotates because of its annular shape and receives vacuurn pressure which it transmits through the openings 98 into the sleeve 18B to create .

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W092/01423 PCT/US9l/0~9~9 2~6~386 negative pressure in the working tip through this elongated sleeve.
With this arrangement, the sleeve 18B is rotated and carries vacuum pressure with it to the tip. The brazed connection 102 aids in transmitting force from the output shaft 90 to the shaft 18B
through the boss 92 by increasing the fir~ness of the connection between the tool sleeve 18~ and the shaft 80.
To mount and support the too] sleeve 18B, the protective sleeve 13A in the embodiment of FTG. 6 includes a cyl.indrical base member 110 having internal teeth 112 a~apted to engage the internal teeth 82 of the housing 72 and is sea].ed against the flow of fluid t~erethrou~h by the O-rings 80 compressed between the enlarged cylinder 110 and the housing portion 72. A narrower outer sheath portion 114 is intergrally formed with the cylindrical portion 110 and receives a cylindrical passageway formed between the inner tool sleeve 18B and its outer tubular surface to permit the flow of irr1gatin~ liquid between the outer protective sleee 13A and the inner member tool sleeve 18~ into the capsular bag.
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'' ' ~ . ' . ' ~ .,~' W092tO1423 P~T/~S91/04959 2~65~6 32 .
With this arrangement, the tool sleeve 18~ can he rotated by the motor ~0 and at the same time~
irrigating flui2 can be applied between it an~ the protective outer sleeve 13A; and ~2) aspirating negative pressure can be applied to pull fragments along its longitudina] axis. At its outer end, the fragmenting tip or bla~es are formed in a manner to be described hereinafter.
In FIG. 7, there is shown a front e.~evational view of one embodiment of a too~ having a sleeve portion 12A and a b.lade portion 14B with two blade members formed in its outer end and separated by an opening 120 longitudinally passing along the longitudinal axis of the tool to ~orm blade portion 14B at the end of the same cylinder forming the sleeve 12A. Both the blade portion 14A and sleeve portion 12A are formed on a sing]e integrally formefl cylinder that serves as the aspirating drive shaft 18~. Aspirating holes extend through the tip of the blade portion 14A orthogonal to the longitudinal axis and the slot 120. To receive some material for aspirating, the aperatures 122 anfl 123 are .
approximately 0.04 inch from the tip 24 of the blade portion 14A and the diameter of the tube 18B is : .
approximately 0.042 inch. The diameter of the ~ "' ' ' 1 ' WO92/01423 PCT/US9l/04959 20653~6 aspirating holes 122 and 123 is 0.018 inch and should not be ]arger than 7 mill;meters.
FIGS. 8 and 9 are a plan vie~ and a right elevatio~al view of the embodiment of FIG. 7, respectively, showing the s].ot 120 having a width of 0.008 inch and extending downwardly approximatelY
0.07 inch. As best shown in FIG. 8, the edges of the walls of tube or sleeve 18B along the s~ot have a larger or blunter trailing edge shown at 126 and a sharper leading edge at 124 in one embodiment as well as a blunter edge at 130 and a sharper edye at 128 so that the sharper edges as the item rotates counter-clockwise as shown in FIG. 8 e~ongate or cut the tissue withi.n the eye an~ create cavitation at the blunter edge.
In FIG. 10~ there is shown a fragmentary front elevational view of another embodiment showing the tip along the slot brought together, welded and offset to provide a sharper and a blunter edge by offsetting the edges along the slot to a greater degree but without the need for changing the thickness of the tube walls. This embodiment forms a rake angte of 90 degrees and two cutting edges but : slots at three locations in the wall of s].eeve 18B
~ an also be formed instead of two slots 180 degrees : :

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2~3~ 34 apart, providing a 60 degree rak~ angle an~ three cutting edges or fo~r s]ots to provide a 45 degree rake angle and ~our cutting edges. Moreover, the tips can be brought together as in FIG. lO to form a smooth protective dome or can include a cutting edge or be open. the tip can also be twisted, which will change the rake angle along the slot and provide a cyclone fan pulling effect.
To form the embodiments of FI~S. 7-lO, a tubular sleeve is slotted at 120 as shown best in FIGS. ll and 12 and pinched together. The two sides are then offset in space lateral~y in a direction along a plane passing through the center of the slots and the longitudinal axis of the sleeve as shown in FIGS. 13 and 14 and the tips pinched together and braæed together to form a tip such as that shown in FIG. lO. Prior to closing the tips 140, the narrower and blunter edges may be further shaped by cutting one wa]l at a more acute angle than the other wa]~ and then removing the other sides of the slot with a reverse cut so as to form flat cuts and sharpened cuts.
To form other raking angles and shape the ~lade to pull viscous fluid or such viscous fluid; the ends are offset, twisted and brazed as shown in FIG.

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WO92/01423 PCT/USgl/~4959 2~53~6 15 and 16, first offset along a ]ine or plane aligned with the two s~ots and longitudinal axis and then twisted at a slightly different angle to form a different rake angle and cyclone pump effect. ~he tip is normally smooth at the very tip 140 but has a cutting effect as it moves radially outwardly.
In one version of the preferred embodiment, the tube has an outer diameter of 42 thousan~ths (0.042) inch with two diametrica]ly opposed slots. The en~s are moved together in a curvature leaving a s]ot about 8 thousandths inch wide at its widest point and extend from the top approximately 70 thousandths inch (70 thousandths long). ~inety degrees removed from the two slots are centra~ aspirating apertures having a diameter of 18 thousandths of an inch and being circular in cross section. They are located with their bottom edge generally adjacent to the end of the slots.
The tube usually rotates at approximately 1600 hertz when fragmenting the nucleus in a preferred embodiment having two cutting edges and the wedged surfaces o the s]ots have one edge that is in a range of 1 thousandths of an inch to twenty ~thousandths of an inch thick and a trailing edge that is in the range of ten thousandths of an inch . :..
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WO92/01423 PCT/VS91/049~g ~53~6 to fifty thousandths o~ an inch thick. Preferably, it should be in the range of 300 hertz to 4000 hertz but may be slower or faster when at a ]ocation in the capsular sac not near tissue to be preserved or which may be moved to change other tissue. The slots and rate of rotation are selected to provide, in the preferred embodiment, a surface moving 200 centimeters a second at the ~astest point on the curved moving surfaces and preferab]y ~o provide a surface moving at the fastest point within a range of 5 meters a second to 40 centimeters per second at the fastest point bu~ may move slower or faster under some circumstances.
Since it is a rotating ,surface which curves inwardly toward the center, the speed is very low at the center and under some circumstance~ does little fragmentir.g at the center and more and more fragmenting as the' rotating radius increases to the sleeve radius. The slot is next to tissue for a very short time such as between 10 milliseconds and 1 mil~isecond. Each cutting edge sweeps past a point about once every 625 microseconds, preferab~.y, or in the normal range of once every 3 mi].liseconds to once every 400 microseconds.

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WO92/01423 PCT/US91/04~59 26~386 ' In addition to zones of a sph~re and sections of a cylinder intended ~or use within an eye, other shapes of moving sur~aces may be used an~ the tool has uses other than for cataract removal such as in vascular operations. ~or examp]e, multiple zones of a sphere may be spaced from each o~her at a shorter distance so that the item need not be rota~ed as fast and motion other than rotational motion may be used to prevent entrance of the tissue into the fragmenting zone. A convenient embodiment for removing structures around veins or arteries duriny vascu]ar operations is dumbel~ shaped so that a ;
recess fits around the vein while spherical cutting zones are positioned on either side of the vein. ~ ;
In some embodiments, the moving surface is formed of a curved member attached to a rotatable shaft having a sharpened edge at an angle of between 0 and 60 degrees but preferably 45 degrees with a surface of revolution which surface has a center of rotation aligned with the rotating shaft. ~he :
sharpened edge of ~he curved member may face away from the center of rotation so that the cutting action of the sharpened surface is into the cortex and core material Oe a cataract. ^`

:
., . ' ~ ~ ~ 5 ~ 38 In FIG. 17, there is shown a block diasram generally illustrating the steps in a cataract extraction and lens implantation techniq~e 50 comprising: (1) the step 52 which inc~udes the preliminary substeps of maintaining the anterior chamber and making the incision into ~he capsular wall; (2) the step 54 of fragmenting and removing thç lens and t3) the step 5~ which includes the substeps necessary for implanting the lens.
In performing this technique, the step 52 which includes the substeps required to make the incision and maintain the anterior chamber and the step 56, which includes the substeps necessary for implanting are not by themselves new and many of the steps are described in Anis, Aziz Y., "Illustrated Step-by-Step Description of the Anis Dry Extra Capsular Cataract Extraction Technique With In-the-Bag Lens Implementation", Seminars in Opthalmo~o~y, v. 1, ~.
2 (June), 1986, pp. 113-129. Moreover, the removal of the lens may not be followed by imp~antation but may be part of a treatment in which the aphakia is treated by contact lens or g~asses.
~ he step 54 of fragmenting and removing the lens includes: (1) the step of inserting the handpiece; (2) the step of extending the blades in ~ .

WO92/01423 PCT/US9l/04959 5 3 ~ 6 some em~odiments within the capsular bag, and ~3) the step of breaking and removing the hardened part of the nucleus. These steps are al] performed through a small incision while the anterior cham~er is maintained with a viscoelastic medium.

Hydrodelineation may be performe~ as described in Vnite~ States patent 4,908,015, if desired, but such hydrodelineation is not part of this invention.
The step 52 which includes preliminary substeps of maintaining the anterior chamber and making the incision in the capsular bag includes the substep of making a small incision in the capsular bag, preferably no greater than 3 millimeters in length and in the range of 1 to 2 millimeters. This incision is made while the anterior chamber is maintained an~ is made as small as possible to maintain the structure of the capsular bag to the .;,,,~.~,~
extent possible. Through this sma]1 incision, the step 54 of fragmenting and removing the lens and the step 56 of implanting a lens are performed. Under some circumstances, the incision may be 4 or 5 millimeters but should always be less than 7 millimeters. `
With the posterior capsule in focus in the foca~ plane of the microscope, the handpiece 10 is ~: .

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intro~uced through an incision shown at 220 in FIG.
13 in the wall of the capsulary sac. The tip of a handpiece 10 is thrust through the incision in the wall of the capsular bag and into the lens therein.
The blades are rapidly rotated while slight negative pressure is applied to aspirate the fragments. The rotating blades are inserted gradually into the cortex and nucleus and from time to time a small amount of irrigating fluid :is injected. Fragmented cortex or nucleus material is aspirated. After removal of the cataract and the handpiece with the capsu].ar sac relatively intact, a lens implant is inserted through a relatively small opening as described in the above pubJ.ication of Anis.
Generally, the nucleus is first removed then the cortex. The surface - discriminating fragmenting handpiece fragments an~ permits aspiration of the cotex an~ nucleus without damaging nearby smooth wa].ls of the capsular sac7 It avoids fragmenting the smooth walls with its cutting edges but fragments rougher, stiffer higher mass tissue, : moving it into a negative pressure zone for aspiration~ The smooth more flexible, lower mass .
surfaces are moved by the b].ades which hit it at an ' .
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.
:~ ' :''' W O 92/01423 PC~r/US91/04959 41 ~06~386 angle. The tissue being frag~ented is hit at an angle and subject to cavitation rapidly and repeatedly with a force each time that does not move the entire material to the extent that it may damage the capsular wall or other hea].thy tissue that is not to be fragmented but does fragment the cortex.
~ he surface discrimination of the instrument is controlled by moving surfaces which permit the diseased higher mass tissue to be fragmented but which move at a rate of speed and have openings between them of such a size that the more integrated .: . . . ..
f].exible, lower mass and smoother tissue does not fall within their fragmenting zone. The tissue is not constrained by opposed shear forces of the instrument but are free to move and the cutting edge of the instrument cuts tissue that: ~1) is stiffer and has a higher modulus of rigidity; and (2) is at an angle to the cutting edge closer to 90 degrees and receives less force moving it away.
Thus, the surgeon removing a cataract adjusts the speed of movement of the cutting eclge to cut cortex with a higher mass and modulus and more projections in the path of the cutting surface and not the capsular wall with a lower modul~s and mass - , .. . .
~ ~ and fewer projections closer to 90 deyrees 50 it is ,.
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: , , WO92/01423 PCT/US91/049~9 2~6~'8~

more readi]y moved away from the cutting edge. The aspirating pressure is low eno~gh to pull the fragmented tissue b~t not the smooth wall. ~he rotating s~rfaces move the smooth wall outwardly and provide some counter pressure to the aspirating pressure inside the cutting zone.
As can be und ers tood from the above description, the technique and equipment of this invention has several advantages, such as: (1) they selectively fragment some tissue ~ithout damaging other nearby tissue; and (2) thev are able to fragment, mix and aspirate tissue and in the case of cataract removal a]so scrub the capsular wall without damaging it, all with one instrument.
Although a preferred embodiment of the invention h as be en d escribed wi th som e particularity,`many modifications and variations are possible in the preferred embodiment ~ithout deviating from the invention. Thereforer it is to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

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Claims (26)

What is claimed is:

1. A method comprising the steps of:
inserting a surface discriminating fragmenting tip having fragmenting surfaces through an opening in the eye into the lens of an eye having a cataract and a capsular wall wherein the tip has movable spaced apart fragmenting surfaces;
moving the fragmenting surfaces at a velocity faster than the fragmenting velocity with respect to tissue of a cataract and lower than the fragmenting velocity of the capsular wall;
positioning the surface discriminating fragmenting tip to impact said tissue of the cataract while it is moving at a velocity higher than the fragmenting velocity with respect to the capsular wall and at an angle to the cataract;
whereby the cataract fragmented but not the capsular wall; and aspirating the fragmented tissue.

2. A method in accordance with claim 1 wherein the fragmenting surfaces are moved at a rate that sweeps tissue once during a time period of between 400 microseconds and 3 milliseconds at an angle to the tissue, wherein at least some fragmenting surfaces cause sufficient cavitation to fragment tissue.

3. A method according to claim 2 wherein the fragmenting surfaces are moved with sufficient momentum and kinetic energy so that the speed remains relatively constant during fragmenting.

4. A method according to claim 3 further including the steps of:
making a small incision less than 7 millimeters in diameter in the capsular sac along the margin;
inserting a fragmenting tip and rotating the fragmenting tip to fragment a cataract.

5. A method according to claim 4 further including the step of rotating the fragmenting surfaces about a longitudinal axis of the surface discriminating fragmenting tip in which the step of inserting the tip includes the step of inserting the tip with the longitudinal axis making an acute angle with the capsular wall wherein the rotating fragmenting surfaces impact the tissue of the cataract at an angle.

6. A method according to claim 1 wherein the fragmenting surfaces are moved with sufficient momentum and kinetic energy so that the speed remains relatively constant during fragmenting.

7. A method according to claim 6 further including the steps of:
making a small incision less than 7 millimeters in diameter in the capsular sac along the margin;
inserting a fragmenting tip and rotating the fragmenting tip to fragment a cataract.

8. A method according to claim 1 further including the step of rotating the fragmenting surfaces about a longitudinal axis of the surface discriminating fragmenting tip in which the step of inserting the tip includes the step of inserting the tip with the longitudinal axis making an acute angle with the capsular wall wherein the rotating fragmenting surfaces impact the tissue of the cataract at an angle.

9. A method according to claim 1 in which the fragmenting tip is rotated with a power level of less than 1 horsepower.

10. Apparatus for removing tissue from a patient comprising:
means for fragmenting and aspirating tissue having an operative tip;
said means for fragmenting and separating tissue comprising means for repeatedly moving the operative tip under the control of an electrical signal at a low power level and at a velocity above a fragmenting velocity of the tissue and at an angle to the tissue;
said operative tip having at least one fragmenting edge with open spaces of less than 10 millimeters.

11. Apparatus in accordance with claim 10 in which the operative tip includes a cutting end and a cavitation-creating surface.

12. Apparatus according to claim 11 in which space between fragmenting edges is less than 5 millimeters.

13. Apparatus according to claim 12 in which the means for moving includes a means for rotating the operative tip.

14. Apparatus according to claim 13 in which the operative tip has a diameter of less than 7 millimeters.

15. Apparatus according to claim 14 in which the operative tip is hollow and includes slots extending generally in a plane parallel to the longitudinal axis of the operative time, said slots having a leading edge and a trailing edge.

16. Apparatus according to claim 15 in which the means for moving includes means for moving the fastest moving point on the leading edge at a rate that is in the range of 49 centimeters per second and 5 meters per second.

17. Apparatus according to claim 10 in which the operative tip is replaceable.

18. Apparatus according to claim 10 in which the means for moving includes a means for rotating the operative tip.

19. Apparatus according to claim 10 in which the operative tip is hollow and includes slots extending generally in a plane parallel to the longitudinal axis of the operative time, said slots having a leading edge and a trailing edge.

20. Apparatus according to claim 19 in which the means for moving includes means for moving the fastest moving point on the leading edge at a rate that is in the range of 5 centimeters per second and 40 meters per second.

21. Apparatus according to claim 10 in which the means for moving includes means for moving the fastest moving point on the leading edge at a rate that is in the range of 5 centimeters per second and 5 meters per second.

22. A method comprising the steps of:
surgically opening tissue to expose a tumor near a tubular health membrane;

inserting a surface discriminating fragmenting tip through the opening against the tissue wherein the tip has movable spaced apart fragmenting surfaces, moving the fragmenting surfaces at a rate higher than the fragmenting velocity of the tumor with respect to the tumor but slower than the tubular healthy membrane with respect to the healthy membrane; whereby the tumor is pulverized; and aspirating the pulverized material.

23. A method in accordance with claim 22 wherein the fragmenting surfaces are moved at a rate that sweeps across the smooth surfaces once during a time period of between 400 microseconds and 3 milliseconds.

24. A method of making an operative time for tissue fragmentation comprising the steps of selecting a metal tube having a diameter lower than 10 millimeters and slotting one end and adapting the other end to be rotated.

25. A method according to claim 24 further including the step of offsetting the end portions left after slotting and bending their tips together.

26. A method according to claim 26 further including the step of twisting the tip after offsetting.