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Claims  |
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I claim:
1. An ultrasonic probe tip for removing unwanted material and reducing said
material into smaller particles for aspiration comprising;
a body section and a distal section said body and distal sections being
adapted to receive ultrasonic vibratory energy from a source and to convey
said vibratory energy to said material disposed in coupled relationship to
the body section, the body section being spaced from the distal section in
the direction of removal of the unwanted material;
an annular edge on said distal section to remove the material and reduce
such material to smaller particles; and
passage means extending through said body and distal sections and
communicating with the annular edge for the withdrawal of the particles
from the tip by aspiration, said passage means having vortex action
generating means including a relatively small diameter passage disposed in
said body section and an extended and enlarged chamber disposed in said
distal section and communicating directly with said relatively small
diameter passage in said body section in the direction of movement of the
smaller particles of the unwanted material through the passage means; said
relatively small diameter passage defining a core stream drawn into and
through said extended and enlarged passage in said distal section whereby
vortex action is generated in the enlarged chamber by boundary layer
effect to clear the unwanted material, assist in reducing the size of the
particles to prevent clogging in said passage means and to prevent
cavitation.
2. The probe tip of claim 1 wherein the inner surface of said enlarged
chamber in said distal section is roughened to further assist in reducing
the size of the particles.
3. The probe tip of claim 2 wherein the roughened surface in said enlarged
chamber is etched.
4. The probe tip of claim 1 wherein said tip has an annular cross-sectional
shape of a substantially constant outer diameter in the body section and
in the distal section for optimizing the ultrasonic action.
5. The probe tip of claim 4 wherein said tip includes a head with a smooth
cylindrical surface.
6. The probe tip of claim 1 wherein said tip is made from titanium.
7. A method of ultrasonically removing unwanted material and reducing said
material into smaller particles comprising the steps of:
providing a hollow tube including a passage at one end of the tube for
particle aspiration and further including an enlargement of the passage at
the other end of the tube and further including a sharpened annular edge
at the end of the passage for particle aspiration, the passage
communicating with the sharpened annular edge;
ultrasonically vibrating the hollow tube;
engaging the material with the sharpened annular edge of the vibrating tube
for removing the material and reducing said material into smaller
particles;
introducing a liquid to the vicinity of the unwanted material to provide
irrigation of such material; and
generating a core stream of the liquid through the passage in the tube
adjacent said tube end to generate a vortex action in the passage by
boundary layer effect in the enlargement in the passage to clear the
unwanted material, assist in reducing the size of the particles to prevent
clogging in said passage and prevent cavitation.
8. The method of claim 7 wherein the passage has a substantially uniform
diameter and communicates directly with the enlargement in the passage to
provide for a circulation of the particles in a vortex ring in the space
beyond and around the end of the tube and an impact of particles against
the shaprened annular edge of the tube for a cutting of the particles into
particles of reduced size.
9. The method of claim 7 wherein is provided the additional step of
roughening the surface inside the enlargement in the passage at the other
end of the tube to facilitate the cutting of the particles.
10. Apparatus for removing a cataract from the eye of a patient wherein a
saline solution is introduced to the patient's eye comprising:
means for generating energy at an ultrasonic frequency,
a probe tip attached to said energy generating means, said tip having an
interior passage and a cutting edge, said energy generating means
vibrating the tip at the ultrasonic frequency, the interior passage
communicating with the cutting edge,
the interior passage having a first particular diameter at an end displaced
from the cutting edge and an enlargement in a portion of the probe tip at
an end adjacent the cutting edge, the enlargement of the passage having a
second particular diameter and communicating directly with the interior
passage of the first particular diameter and having a sufficient axial
length to generate a clearance and a circulating area of particles around
the cutting edge of the tip to assure maximum cutting of the particles by
the cutting edge, and
means for aspirating the saline solution and particles of the cataract from
the patient's eye.
11. Apparatus as set forth in claim 10, wherein said enlargement of the
passage is of a diameter and axial length relative to the passage of the
first particular diameter to emulsify the particles in said passage.
12. Apparatus as set forth in claim 10, wherein the energy-generating
means, the probe tip and the aspirating means are in axial alignment.
13. In combination for use in removing a cataract from a patient's eye:
means for providing vibrations at an ultrasonic frequency,
a probe tip coupled to the vibrating means for vibration at the ultrasonic
frequency and having a cutting edge,
a passage, said passage extending through said probe tip and communicating
with the cutting edge and having a substantially uniform diameter at the
end of the probe tip displaced from the operative end, and
and an enlargement in the passage at the operative end of the probe tip
adjacent the cutting edge and communicating directly with the passage of
substantially uniform diameter to provide a clearance and a circulating
area with a vortex action in the enlargement for enhancement of the
cutting action and for an emulsifying action on the particles during the
vibration of the probe tip at the ultrasonic frequency.
14. In the combination as set forth in claim 13, wherein the enlargement in
the passage at the operative end of the probe tip has a diameter and an
axial length to facilitate movement of particles against the cutting edge
for enhanced cutting action.
15. In the combination set forth in claim 14, wherein the outer diameter of
the probe tip is substantially constant.
16. In the combination as set forth in claim 15, wherein the surface
defining the enlargement in the passage in the probe tip is roughened.
17. In the combination set forth in claim 13, wherein said enlargement of
the passage is defined by an inner wall roughened to facilitate the
emulsifying action on the particles.
18. A probe tip for use in removing a cataract from the eye of a patient
comprising:
a cylindrical tube adapted to be vibrated by ultrasonic vibration in
intra-operative use,
a cutting edge provided at one end of the tube, and
a passage extending through the tube and communicating with the cutting
edge, said passage having a first diameter at the end adjacent the cutting
edge and a second diameter at the end removed from the cutting edge, said
first diameter being greater than the second diameter, the portion of the
passage with the first diameter communicating directly with the portion of
the passage with the second diameter whereby, upon an ultrasonic vibration
of the tube, a clearance and a circulation area are provided around the
cutting edge to facilitate the formation of the removed portions of the
cataract into particles.
19. The probe tip as set forth in claim 18, wherein said first passage
includes an interior wall having a roughened surface.
20. The probe tip as set forth in claim 19, wherein said probe tip is
fabricated from titanium.
21. The probe tip as set forth in claim 18, wherein said cutting edge of
the tube is hardened and the outer diameter of the tube is substantially
constant. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention pertains generally to ultrasonic probes and, more
particularly, to an improved ultrasonic probe tip which emulsified and
more efficiently removes tissue as it is aspirated through the tip.
Until the late 1960's, ophthalmological surgical techiques for cataract
removal were performed using standard intracapsular cataract extraction
techniques which, although generally satisfactory, require a prolonged
recovery time of up to several months. Since that time, a procedure known
as phacoemulsification, or use of an ultrasonic probe to break up and
remove cataracts, has become widely used because it offers a remarkable
decrease in recovery time. Indeed, a patient can sometimes return to work
the day after surgery with this new technique.
The procedure for removal of cataract tissue is described in the article
entitled "History of Emulsification and Aspiration of Senile Cataracts,"
by Charles D. Kelman, appearing in Transactions American Academy of
Ophthalmology and Otolaryngology, Volume 78, January-February, 1974, pp.
OP5-13 (originally presented at the 78th Annual Meeting of the American
Academy of Ophthalmology and Otolaryngology, Dallas, Tex., Sept. 16-20,
1973). Generally speaking, a tip in the form of a hollow tube is inserted
into the anterior chamber of the eye through a small incision into contact
with the cataract tissue. The tip is vibrated by a hand held probe at an
ultrasonic rate, and hydrodynamic flow of a saline solution is
estabilished in order to prevent collapse of the anterior chamber. As
particles of the cataract tissue are cut from the cataract mass, the
particles are removed from the chamber through the tip of the ultrasonic
probe. In the case of hard cataracts, these particles, which have a
tendency to slide into contact with the walls of the chamber, have an
abrasive character. Since certain portions of the eye including the
chamber walls are very prone to abrasion sensitivity, the cataract
particles must be quickly, and as completely as possible, removed from the
chamber. This is done by aspiration through the hollow tip.
During aspiration of cataract tissue, the tip of the ultrasonic probe must
be very carefully manipulated under the field of view of a microscope in
order to prevent aspirating other than cataract tissue and to insure that
all the cataract particles are removed from the chamber. Close control of
the tip is especially critical at the peripheral regions of the cataract.
The tip must be able to efficiently remove the cataract tissue without
clogging or otherwise hindering the surgical procedure.
Several improved ultrasonic probes have been developed for performing this
and other delicate types of surgery as well as cleaning of teeth and the
like. These probes generally also consist of a tip for cutting/cleaning
material at the operation site, a hand piece for mounting the tip and
associated circuitry, and a pieoelectric crystal or other means for
supplying ultrasonic energy to vibrate the tip. My prior design disclosed
in U.S. Pat. No. 4,169,984, is one of the most innovative, greatly
improving the ultrasonic handpiece capable of use with a variety of tips
for removing cataract tissue, cleaning and similar functions. While
remarkable advances have thus been made in the total instrument and the
technique of use, the basic design of the tips has remained unchanged over
the years. U.S. Pat. No. 4,428,748 to Peyman et al., issued in 1984, is
typical of the attempts that have been made to modify the probe tip. In
this instance an additional drive mechanism is required in an attempt to
provided better cutting action. However, even with this expensive
modification, such designs, like other prior art inventions that I am
aware of, are hampered by slow cutting action, clogging and generally
unsatisfactory performance.
To put it another way, prior ultrasonic probe tips have not proved to be as
effective and efficient in removing the undesired tissue as they could be.
The cutting edge of the probe tip often shears large pieces of cataract
tissue which cannot easily be aspirated with the smal diameter tip. These
particles tend to either not be aspirated and, therefore, left in the eye
to damage walls of the eye, or, as is often the case, clog the tip and
prevent aspiration of the particles. If the tip clogs, surgery must be
halted to clean or change the tip. The delay in surgery increases the
trauma and risk to the patient. A new and improved ultrasonic probe tip
which can efficiently remove severed tissue, emulsify the tissue into fine
particles and avoid the surgical delays caused by tip clogging is,
therefore, needed.
Accordingly, one object of the invention is to provide a new and improved
probe tip for ultrasonically removing tissue.
A further object of the present invention is to provide a new and improved
ultrasonic probe tip which will not clog during the surgical procedure.
Another object of the invention is to provide a new and improved ultrasonic
probe tip for performing phacoemulsification for cataract removal.
Still another object of the invention is to provide a new improved and low
cost probe tip and method for performing cataract particles are
phacoemulsification wherein cataract particles are efficiently aspirated
from the anterior chamber to avoid damage to delicate eye tissue.
BRIEF DESCRIPTION OF THE INVENTION
An ultrasonic probe tip for removing tissue from a surgical site,
particularly for removing cataract tissue from within the eye, comprises a
hollow needle-like tube having a sharp annular end for cutting away the
undesirable tissue and a hollow inner passage for aspiration of the
removed tissue. The inner passage has at least two different diameters
along the tip; the distal or cutting section of the tip having a larger
inner passage diameter than the body section. The passage in the distal
section, therefore, forms an enlarged chamber having a relatively thin
wall while the body section forms a smaller passage having a relatively
thick wall. The larger chamber in the distal section is formed by reducing
the thickness of the tip wall from the interior. The outer diameter of the
tip remains constant for the length of the tip to provide optimum
ultrasonic vibratory action.
As the tissue particles are severed from the cataract or other unwanted
growth, the sharp annular end is more effective in chopping the particles
into fine pieces. The boundary layer of the aspirated core stream defined
by the reduced inner passage in the body section of the tip, sets up an
exterior vortex ring around the end of the tip clearing the operation site
and causing the particles to repeatedly come in contact with the sharp
edge.
As these reduced particles are aspirated through the tip, additional vortex
action generated by the stream and the difference in diameter of the inner
passage causes the tissue particles to be further emulsified. Cavitation
is advantageously prevented by the boundary layer pumping effect as liquid
from the surrounding operation site is pulled into the chamber.
Preferably, the inner surface of the enlarged chamber is roughened, such as
by chemical etching. The particles are stirred and caused to impact the
roughened interior of the chamber many times. Multiple impacts with the
rough surface emulsify the large tissue particles, breaking them into many
small particles, and making aspiration of the particles easier. The tip,
thereafter, ca be used for prolonged periods without clogging caused by
the large tissue particles. Delays in surgery and the resulting trauma to
the patent caused by clogging in prior art tips are greatly reduced or
eliminated.
Other objects, advantages, and novel features of the present invention will
become apparent from the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side cross-sectional view of an ultrasonic probe tip showing
the configuration of the tip of the present invention illustrating the
structural features that allow more efficient tissue removal and
emulsification;
FIG. 2 is a cross-sectional view of the tip mounted on an ultrasonic
generator handpiece for use; and
FIG. 3 is an enlarged cross-sectional view of the cutting end ofthe tip
showing the actual cutting and emulsification action that takes place on a
cataract or the like.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, an elongated ultrasonic probe tip 10, used for
ultrasonically removing cataract tissue or other unwanted material is
shown in its preferred form. Within the tip 10 is an inner passage 12
running the full length as shown in the drawings. The tip is divided into
three sections, a head section 14, a body section 15 and a distal or
cutting section 16. The head section 14 includes a cylindrical flange 17
and a threaded connector 18. Inside the head 14 is an aspiration collector
passageway 19.
As best shown in FIG. 2, the head section 14 of the tip 10 is designed to
be attached to a complete ultrasonic handpiece H. Thus, the tip 10 is
supported on an ultrasonic driver 20 having a hollow interior and
connected to a suitable aspirator 21 and ultrasonic vibrator 22. As is
known in the art, the aspirator 21 is connected to the collector
passageway 19 to form the aspiration means for the tip 10 after being
connected by the threaded portion 18. As shown, the sections 15, 16 have a
constant outside diameter to provide a smooth tubular surface and the
flange 17 is also perfectly smooth, that is cylindrical without any raised
edges. This enhances the ultransonic vibratory action from the driver 20
so that the maximum cutting action is transmitted to the tip 10.
When a surgeon is ready to use the tip 10 of the present invention,
assuming that removable skirt 23 is detached from housing 24 of the
handpiece H, the head section 14 is threaded into the driver 20 so that it
is initially hand tight (see FIG. 2). With a special wrench engaging the
flange 17, disclosed and claimed in my copending patent application
entitled Wrench Assembly for Securing and Removing a Tip from an
Ultrasonic Probe, filed Jan. 13, 1986, Ser. No. 818,013, the tip 10 is
firmly tightened. The skirt 23 is placed back in position on the housing
24, the aspirator 21 and the ultrasonic vibrator 22 is turned on. A
separate supply of saline solution from a supply tube (not shown) is
positioned adjacent the operation site and the operation is ready to
begin. In the case of a cataract operation, the cutting section 16 of the
tip and the solution supply tube is placed in an incision in the eye and
the successful phacoemulsification commences in a manner as will be
described in detail below.
First, with reference to FIGS. 1 and 3 in combination, a more detailed
description of the inventive aspects of the tip 10 of the present
invention is required. The tip 10, as briefly described above, is a
needle-like hollow tube with the body section 15 and the cutting section
16 forming the improvement that provides for the more efficient cutting
and emulsification action. Specifically, the passage means 12 includes an
enlarged chamber 25 in the cutting secton 16. The chamber 25 is formed by
machining a larger inner passage diameter than in the body section 15. The
enlarged chamber 25 thus has a relatively thin wall while the passage in
the body section 15 is thicker. The thicker body section wall provides the
required support along the body section, whereas the thin wall of the
cutting section also provides for a thinner and thus sharper annular
cutting end 26. The outer diameter of the probe tip 10 remain the same
along the entire length from the head 14 to the end 26 providing for the
optimum ultrasonic vibratory action.
As is well known, the operation site, such as in a cataract operation, is
flooded with liquid solution, preferably a saline solution. This maintains
the material being operated on and the particles being removed in
suspension thus allowing efficient hydraulic aspiration through the
passage 12. The operation site flooded with liquid solution is depicted in
FIG. 3 where a cataract C is being operated on with an annular vortex ring
being defined by removed particles C1 around the perimeter of the cutting
end 26. The showing of FIG. 2 depicts the tip 10 having removed a portion
of the cataract C generating the particles C1 and having backed away
slightly from the operation site to allow the particles C1 to be broken
up, emulsified and aspirated through the passage 12. The skilled surgeon
deftly moves the tip 10 toward and away from the operation site
alternately cutting away and allowing full aspiration of the particles
until the entire mass C is disintegrated.
As the aspiration is established through collector passageway 19 and the
passage 12, a core stream S is generated in the operation area, as
depicted by the dashed/dot line outline in FIG. 3. As shown, this core
stream is generally the size of the reduced inner passage within the body
section 15 and is made up of the fastest moving liquid molecules. The core
stream starts adjacent the operation site and extends through the enlarged
chamber 25.
As the core stream moves through the flooded operation area, the boundary
layer tends to entrain the surrounding liquid molecules setting up a
desired vortex ring around the annular end 26 (see FIG. 3). This vortex
ring is generally depicted by the action arrows A. This vortex ring
action, although not understood in its entirely, is believed to perform
two important functions that have not been possible with ultrasonic probe
tips of the prior art without an enlarged distal chamber; namely, (1) a
clearance of the operation site around the cataract C (note space between
the particles C1 and the cataract C) and (2) a circulating movement of the
particles C1 so as to be brought repeatedly into engagement with the
sharpened annular end 26 for splitting, resplitting and emulsification
into smaller and smaller particles.
Inside the enlarged chamber 25, additional vortex action is generated by
the stream and the difference in diameter of the inner passage. The
particles within the chamber are further emulsified as the liquid
moleculars stir and agitate the particles breaking them apart. In this
regard, note the action arrows B in FIG. 3.
Preferably, in accordance with a more limited aspect of the present
invention, the probe tip 10 is fabricated of titanium and the inner
surface of the chamber 25 is roughened, such as by etching of the metal
surface. This roughening can be by chemical etching using hydrochloric
acid, for example, or can be by mechanical scoring of the metal. The
multiple impacts of the particles with the roughened interior of the
chamber serve to further emulsify the particles breaking them into smaller
and smaller particles and making aspiration easier and helping to
virtually eliminating clogging of the tip 10.
Another drawback of prior art tips is avoided by the enlarged chamber 25 of
the present invention. That is, deleterious cavitation or formation of air
pockets around the operation site, at the mouth of the tip and along the
passage 12 is avoided. This advantageous action is also attributed to the
benefits of the core stream with the boundary layer pumping serving to
effectively draw surrounding liquid to the operation site and into the
chamber 25. Since the stream S is spaced from the surface of the chamber
25, there is room for the additional liquid to enter and collapse any air
pockets that would tend to form along the surface. To put it another way,
the space prevents complete evacuation along the surfaces which previously
would have led to air pockets, as is well known in the art of fluids and
particularly the art of fluidics. Without cavitation, the flow of fluid
remains smooth and constant eliminating a significant source of clogging
and indeed minimizing trauma to the operation site.
In summary, the probe tip 10 of the present invention having an enlarged
distal chamber 25 provides significant results and advantages over the
prior art tips. During a phacoemulsification operation or the like, the
ultrasonic cutting of the unwanted tissue and the breaking up and
emulsification of the particles is substantially enhanced. The core stream
S defined by the passage 12 in the body section 15 of the tip 10 provides
for a smooth circulating action in a vortex ring around the sharpened
annular end 26. The operation site is cleared continually and the
particles are caused to have multiple impacts against the end for more
efficient splitting and emulsification. The probe tip 10 can therefore
access the operation site more easily, do a better job emulsifying the
particles and prevent clogging, thus significantly reducing the time
required for the surgery. The vortex action within the enlarged chamber 25
and the roughened surface further emulsifies the severed tissue and aids
in the removal procedure. The boundary layer effect fills in any voids
around the operation site or within the enlarged chamber 25, thus
virtually eliminating cavitation and providing for the first time smoother
and more efficient liquid flow.
Obviously, many modifications any varations of the present invention are
possible in light of the above teachings. It is therefore to be understood
that within the scope of the appended claims, the invention may be
practiced otherwise than as specifically described.
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