A cutting head for attachment to the end of the wire probe of an ultrasonic kidney stone disintegration instrument. The cutting head has a plurality of circumferentially arranged teeth formed at one end thereof to provide a cup-shaped receptacle for kidney stones encountered during the disintegration procedure. An integral reduced diameter collar diminishes stress points in the wire and reduces breakage thereof

Angulo, Earl D.

Goodfriend, Roger

NASA Technical Reports Server

United States Patent [I9J 
Angulo et al. 
[54] CUTITNG HEAD FOR ULTRASONIC 
LITHOTRIPSY 
[75] Inventors: Earl D. Angulo, Silver Spring, Md.; 
Roger Goodfriend, Los Gator, Calif. 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronuautics & Space 
Administration, Washington, D .C. 
[21] Appl. No.: 793,006 
[22] Filed: Oct. 30, 1985 
[51] Int. 0.4 ... .... .. .. ....... .. . ..... . ........ .. ........ . A61B 17/22 
[52] U.S. 0 . .. .. .............................. 128/ 328; 128/24 A 
[58] Field of Search ... ........................... 128/24 A, 328 
[56] References Cited 
U.S. PATENT DOCUMENTS 
3,823,717 7/ 1974 Pohlman et al. .................... 128/ 138 
3,830,240 8/ 1974 Antonevich et aI ..... ........... 1281138 
22 
54 
[I IJ Patent Number: 
[45] Date of Patent: 
4,823,793 
Apr. 25, 1989 
3,857,396 12/1974 Hardwick ............... .... .... .. .. 128/ 335 
3,896,811 7/1975 Storz ...... .. ........................... 128/ 138 
4,178,935 12/1979 Gekhman et al. .................. 128/ 138 
4,474,180 10/ 1984 Angulo .... .. .. .. .......... .. .. . 128/24 A X 
4,572,184 2/1986 Stohl et al. .. .. ....... .. .... .. ....... 128/ 328 
Primary Examiner-Michael H. Thaler 
Attorney, Agent. or Firm-R. D. Marchant; John R. 
Manning; John O. Tresansky 
[57] ABSTRACT 
A cutting head for attachment to the end of the wire 
probe of an ultrasonic kidney stone disintegration in-
strument. The cutting head has a plurality of circum fer-
entia1ly arranged teeth formed at one end thereof to 
provide a cup-shaped receptacle for kidney stones en-
countered during the disintegration procedure. An inte-
gral reduced diameter collar diminishes stress points in 
the wire and reduces breakage thereof. 
7 Claims, 1 Drawing Sheet 
16 
24 
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32 
38 
(PRIOR ART) 
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CUlTING HEAD FOR ULTRASONIC 
LITHOTRIPSY 
ORIGIN OF THE INVENTION 5 
wire probe for a length of time adequate for completion 
of the procedure. A desirable time frame is typically one 
minute, which is substantially greater than that pro-
vided by known prior art apparatus. 
STATEMENT OF THE INVENTION 
Accordingly, it is an object of the invention to pro-
vide a cutting head for surgical use. 
The invention described herein was made by an em-
ployee of the U.S. Government and another and may be 
manufactured and used by or for governmental pur-
poses without the payment thereon or therefor. 
TECHNICAL FIELD 
Another object of the present invention is to provide 
10 a cutting head member for an ultrasonically vibrated 
wire probe. 
A further object of the instant invention is to provide 
a safer and more efficient cutting head for ultrasonically 
disintegrating kidney stones. 
This invention relates to surgical apparatus for disin-
tegrating urinary calculi, and, more particularly, to a 
cutting head and to an ultrasonic device for fragmenting 
or drilling through urinary calculi in situ. 15 Still another object of the invention is to provide an 
BACKGROUND ART 
The incidence of hospitalization for the removal of 
urinary calculi, commonly referred to as kidney stones, 
has been estimated to be as high as 200,000 cases per 20 
year. Stones which are quite small may in some cases be 
passed without hospitalization. However, in the remain-
der, the kidney stones become impacted in the ureter, a 
muscle tube joining the kidney to the bladder. An im-
pacted kidney stone is a source of intense pain and 25 
bleeding, a source of infection, and, if the stone com-
pletely blocks the flow of urine for any extended length 
of time, can cause the loss of a kidney. Small stones 
which are lodged in the lower third of the ureter can be 
removed non-surgically by using a technique employ- 30 
ing the well known Dormia stone basket. However, 
basket removal of a kidney stone usually fails if the 
stone is lodged in the upper ureter, is impacted, or is 
larger than one centimeter in diameter. In these cases, 
the only procedure by which the stone could heretofore 35 
be removed was through a serious surgical operation 
called a ureterolithotomy. 
More recently, however, a non-surgical method for 
removing kidney stones has been developed. In this 
technique, the kidney stones are subject to a vibratory 4Q 
action, such as that provided by an ultrasonically vi-
brated wire probe. In one such apparatus, a catheter is 
placed cystoscopically at the site of the stone in the 
urinary tract, after which a long wire probe is passed 
through a lumen of the catheter and is brought into 45 
contact with the stone. The wire probe is attached to 
the ultrasonic transducer which, when energized, sets 
the wire probe into lateral and longitudinal vibrations. 
The vibrational energy is transmitted by the wire probe 
to the stone, causing it to fracture into small fragments 50 
which the patient can then pass spontaneously after 
withdrawal of the catheter. 
While such apparatus can perform its intended func-
tion, a severe limitation has been found to exist due to 
slippage of the thin wire probe ofT the kidney stone and 55 
its lodgement between the stone and urinary tract. At-
tempts to ameliorate this situation by providing a wider 
tip cutting surface has resulted in premature breakage of 
the wire probe at the tip exiting the catheter near the 
kidney stone. This occurs because the vibrational en- 60 
ergy, typically 20 KHz in frequency, in conjunction 
with the added cantilevered mass of the larger cutting 
area, causes the wire probe to snap ofT due to metal 
fatigue after 10-20 seconds of operation. This has been 
found to be insufficient time to complete the disintegra- 65 
tion procedure, as well as dangerous because it leaves 
metal fragments in the urinary tract. A clear need, 
therefore, exists to prolong the operational life of the 
improved system for prolonging the operational life of 
an instrument for disintegrating kidney stones. 
Another further object of the present invention is to 
provide a device for seating of kidney stones within a 
cutting head in an ultrasonic lithotripsy procedure. 
Yet another object of the present invention is to 
greatly enhance the fragmentation of kidney stones 
when using ultrasonic lithotripsy. 
These and other objects of the present invention are 
provided by a cutting head which is attachable to the 
end of the ultrasonically vibrated wire probe. The cut-
ting head includes a large diameter cutting section pro-
vided with a plurality of teeth formed on the peri-
phency of one end thereof to present a cup-shaped re-
ceptacle to seat a kidney stone thereon. The member 
also includes a collar integrally formed with the cutting 
tip section to reduce stress points along the probe. 
BRIEF DESCRIPTION OF THE DRAWINGS 
The foregoing, as well as other objects, features, and 
advantages of the invention will become apparent from 
the following detailed description when taken in con-
junction with the appended drawings in which like 
numbers represent the same or similar components 
throughout the several drawings, and wherein: 
FIG. 1 is a side elevational view of state-of-the-art 
apparatus for fragmenting kidney stones; 
FIG. 2 is a side elevational view of the cutting head of 
this invention; and 
FIG. 3 is a longitudinal view, partly in section, of the 
cutting head in contact with a kidney stone. 
DESCRIPTION OF T HE PREFERRED 
EMBODIMENT 
Referring to the drawings, and, more particularly, to 
FIG. 1, there is illustrated an ultrasonic kidney stone 
disintegration instrument in accordance with the prior 
art. The purpose of this Figure is to provide a better 
understanding of the invention to be described in detail 
in conjunction with FIGS. 2 and 3. 
FIG. 1 shows a cystoscope 10 inserted through a 
patient's urethra 12 into a bladder 14. A catheter 16 is 
inserted through the cystoscope 10, the bladder 14, and 
into a ureter 18 until its far end 20 comes into proximity 
to a piece of urinary calculi, hereinafter referred to as a 
kidney stone, 22. A wire probe 24 is inserted through 
the catheter 16 until its far end 26 contacts the stone 22. 
The diameter of the wire probe 24 is substantially 
smaller than the lumen diameter of the catheter 16 so 
that any movement of the wire probe is not restricted by 
the catheter material. The opposite, or near end, 28 of 
the wire probe 24 is connected to the tip 30 of a mov-
3 
4,823,793 
able ultrasonic transducer assembly 32 which is 
mounted on a base 34. The base 34 includes a handle 36 
having a trigger 37 which is connected to the trans-
ducer 32 for adjusting the position of the wire probe 24 
against the stone 22 by a linear translation of the trans- 5 
ducer assembly 32 on the base 34. Base 34 additionally 
includes an outward angular support member 38 which 
includes a connector element in the form of a catheter 
joint 40 for engaging and holding the near end of the 
catheter 16. The terminal portion of the wire probe is 10 
clamped to tip 30 of the transducer 32 by a set screw 42. 
With the catheter 16 and wire probe 24 inserted into 
the ureter 18, end 26 of the probe is optically guided to 
make contact against kidney stone 22. Thereafter, the 
transducer assembly 32 is energized to provide lateral 15 
motion to the wire probe 24 and the probe is gently 
pushed against the stone. 
This apparatus does not operate as desired when tip 
26 of the wire probe slips off the surface of the stone 22 
and slides past it as illustrated in the dotted line position 20 
of tip 26'. In this circumstance tip 26' does not perform 
4 
tooth surface from scraping the urethra. While no spe-
cific configuration for the teeth is necessary, it has been 
found that a suitable arrangement is one where the teeth 
are equidistantly-spaced, three-sided with one comer 
forming the cup-shaped receptacle, and with a tapering 
cross section. 
While not intended to be limiting, the following ap-
proximate dimensions of the cutting head 44 are pres-
ented by way of example only: 
Diameter of cutting tip section 48-0.063 inches 
Length of cutting tip section 48-0.16 inches 
Diameter of collar section 46-0.045 inches 
Length of collar section 46-0.233 inches 
In such a configuration, the member 44 attached to the 
wire probe 24 transmits maximum acoustic vibrational 
energy from the probe to the stone 22. The relatively 
large diameter of cutting tip section 48 increases the 
cutting surface area by a factor of three or more and 
insures maximum contact between wire and stone 22 as 
well as prevents slippage of the wire past the stone. The 
cup-shaped end of the tip 48 induces seating of the stone 
22 on the cutting tip. 
The four teeth 50, 52, 54, and 56 assure maximum 
its intended function. Increasing the surface area of the 
cutting tip causes it to break off from the probe 24 at 
end 20 of catheter 16, at the point of greater stress 
where it emerges from the catheter. 25 fragmentation of the stone 22. Even if the stone 22 is highly irregular in shape and centering of the tip 48 
upon the stone is far from perfect, the stone will frag-
ment when contacted by any portion of the cutting tip. 
With the foregoing in mind, a cutting tip 44 shown in 
FIGS. 2 and 3 is attached to end 26 of the wire probe to 
overcome the problem of wire slippage and to greatly 
increase the cutting surface area. Tip member 44 pro-
vides two structural features, one of which prevents 30 
premature breakage of the wire probe at the point of its 
exiting the catheter 16, while the other assures seating 
of the kidney stone within the tip member 44. 
Member 44 is of stainless steel construction and com-
prises two integrally formed coaxial cylindrical sec- 35 
tions, an elongate collar section 46 which relieves stress, 
and a cutting tip section 48. 
Member 44 is also provided with a central circular 
opening (not shown) which extends completely 
through collar section 46 and through most of cutting 40 
tip section 48. The opening has a diameter sufficiently 
wide so that it is just capable of being slid over wire tip 
26. By inserting wire tip 26 through the opening as far 
as possible into the cutting tip section 48, the end of the 
cutting tip section is arranged to initially abut the kid- 4S 
ney stone encountered. Member 44 is thereafter com-
pressed and swaged to the wire probe 24, such as at 
points 58 and 60 of the cutting tip section 48, thereby 
ensuring its permanent retention thereon. Additionally, 
tip 26 can be undercut so as to present a recessed sur- 50 
face, further enhancing the swaging procedure. 
Collar section 46, has an external diameter larger than 
that of probe 24, but less than the inner diameter of 
catheter 16 and is of sufficient length to insure that it 
only partially extends out of the catheter when it is in 5S 
the operational mode, best illustrated in FIG. 3. 
Cutting tip section 48 has a slightly larger external 
diameter than the external diameter of collar section 46 
but less than the inner diameter of ureter 18. It is pro-
vided with a plurality of cutting teeth, preferably be- 60 
tween three and six. The cutting tip section 48 is illus-
trated in FIG. 2 as having four teeth 50, 52, 54, and 56. 
Teeth 50, 52, 54, and 56 are formed on the periphery of 
one end of the cutting tip section to provide a cup-
shaped receptacle for seating a kidney stone 22. Teeth 65 
50, 52, 54, and 56 are machined directly into the end of 
cutting tip section 48 and are desirably provided with 
flat ends so as to preclude the possibility of a pointed 
The lifetime of the wire probe 24 is substantially 
increased by the provision of an elongate collar 46 
which partially stays within the catheter 16 while the 
cutting tip section 48 is extended against the stone 22. 
The collar 46 greatly lessens the mechanical bending 
loads and stress points imposed on the wire probe 24 by 
the vibrating mass of the cutting tip 48, because the root 
of the mass is within the catheter 16 and not cantilev-
ered away from it. Further, by joining the cutting tip 48 
to the wire probe 24 by a swaged joint 58, 60 rather than 
by soldering, mechanical stresses and fatigue fractures 
are greatly lessened. The life of the assembly has been 
found to exceed four minutes when vibrating at 20 
KHz, thus providing ample time to complete the kidney 
stone disintegration procedure. 
Having thus shown and described the invention in 
specific detail, the same has been provided by way of 
explanation and not limitation and accordingly all modi-
fications, alterations and changes coming within the 
spirit and scope of the invention are herein meant to be 
included. 
We claim: 
1. A surgical cutting head for attachment to an ultra-
sonically vibrated wire probe, comprising: 
a cylindrical cutting tip section having a plurality of 
cutting teeth arranged circumferentially at one end 
thereof, said teeth being equidistantly spaced on 
said one end of said cutting tip section and having 
flat top ends and expanding three-sided cross sec-
tions along the length of said teeth to form a cup-
shaped seat having inwardly projecting intersec-
tions formed by two sides of said three-sided cross 
sections to form cutting edges within said cup-
shaped seat; and 
a cylindrical collar coaxial and integrally formed 
with the other end of said cutting tip section. 
2. The cutting head of claim 1 wherein said collar and 
cutting tip sections are provided with a central bore 
along their common axis, said bore extending through 
said collar and partially through said cutting tip section 
5 
4,823,793 
6 
whereby said head may be slid over the wire probe and 
swaged thereto. 
3. The cutting head of claim 2 wherein the external 
diameter of said cutting tip section is larger than the 
external diameter of said collar section. 
4. Surgical apparatus for disintegrating and dislodg-
ing urinary calculi lodged in the urinary tract, compris-
ing: 
5 
a catheter adapted to be inserted into the ureter to 
come into proximity of the calculi to be dislodged; 10 
a wire probe fed through said catheter; 
teeth to form a cup-shaped seat to abut said calculi, 
said seat having inwardly projecting intersections 
formed by two sides of said three-sided cross sec-
tions to form cutting edges within said cup-shaped 
seat. 
5. The apparatus of claim 4 wherein said cylindrical 
member further includes an elongate collar section cou-
pled to and coaxial with said cutting tip section and 
wherein said member is swaged onto said wire probe. 
6. The apparatus of claim 5 wherein the diameter of 
said wire probe is substantially less than that of said 
catheter and the external diameter of said collar section 
ultrasonic transducer means coupled to said wire 
probe for imparting vibrations thereto; and 
is at least twice as great as that of said wire probe, but 
15 less than the diameter of said catheter. 
a cylindrical member including a cutting tip section 
joined to the end of said wire probe for contacting 
said calculi, said cutting tip section comprising a 
plurality of cutting teeth equidistantly spaced 
about the circumference of one end of said mem-
ber, said teeth having flat top ends and expanding 
three-sided cross sections along the length of said 20 
25 
30 
35 
40 
45 
50 
55 
60 
65 
7. The apparatus as recited in claim 6 wherein said 
collar section partially stays within said catheter when 
said ultrasonic transducer is imparting vibrations to said 
wire probe. 
• • • • • 


Cutting Head for Ultrasonic Lithotripsy

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