Electrode for fiber optic scopes

An electrode for use in fiber optic scopes has a connecting end and a discharge end and includes an elongated flexible center conductor and an inner insulation sleeve extending along and covering the conductor. An outer insulation sleeve extends along and covers the inner insulation sleeve and leaves a gap therebetween to define an irrigant conduit between the inner and outer insulation sleeves. A metallic sleeve extends along the irrigant conduit, the metallic sleeve being of a woven braided material whereby to permit passage of the irrigant through the irrigant conduit. Irrigant input means are in communication with the irrigant conduit. Adjacent the discharge end of the electrode is a balloon for centering the electrode in a duct.

BACKGROUND OF INVENTION 
1. Field of the Invention 
The invention relates to an electrode for use in fiber optic scopes. More 
specifically, the invention relates to such an electrode which includes an 
irrigant conduit integral therewith. The invention also relates to such an 
electrode which further includes a means for centering the electrode in a 
duct. 
2. Description of Prior Art 
Fiber optic scopes, such as nephroscopes, ureteroscopes, cystoscopes and 
endoscopes are used basically to provide access to cavities and ducts in 
the human body thereby reducing the need for surgical procedures. The 
electrodes are passed through the fiber optic scopes to create hydraulic 
shock waves which fragment the calculi. 
Endourological procedures are used to remove such calculi from the kidney 
and ureter. In such procedures using fiber optic scopes, it is necessary 
to supply irrigant in the area of the calculi and the discharge end of the 
electrode both for the purpose of providing an electrical path between the 
hot and cold points of the electrode, and to carry the hydraulic shock 
waves. Under present procedures, irrigant is first supplied in the area 
through the operative channel of the scope, and the electrode is then 
inserted. If further irrigant is required, it is necessary to remove the 
electrode to provide irrigant through the operative channel. The electrode 
is once again inserted. 
As will be appreciated, these steps increase the total time for the calculi 
eliminated procedure. In addition, the removal and reinsertion of 
instruments and electrodes is undesirable and should be kept to a minimum. 
Fiber optic scopes are also used to eliminate calculi from ducts in the 
human body, e.g., the common duct. In procedures of this nature, for 
example, endoscopy, it is desirable to be able to center the electrode in 
the duct adjacent to the calculi. Presently available electrodes do not 
have any facilities for effecting this desirable end. 
SUMMARY OF INVENTION 
It is therefore an object of the invention to provide an electrode for 
fiber optic scopes which overcomes the deficiencies of the prior art. 
It is a more specific object of the invention to provide such an electrode 
which includes an irrigant conduit integral therewith. 
It is a further object of the invention to provide an electrode which 
includes means for centering the electrode in a duct. 
In accordance with the invention there is provided an electrode for use in 
fiber optic scopes having a connecting end and a discharge end and 
including an elongated flexible center conductor and an inner insulation 
sleeve extending along and covering the conductor. An outer insulation 
sleeve extends along and covers the inner insulation sleeve and leaves a 
gap therebetween to define an irrigant conduit between the inner and outer 
insulation sleeves. A metallic sleeve extends along the irrigant conduit, 
the metallic sleeve being of a woven braided material whereby to permit 
passage of the irrigant through the irrigant conduit. Irrigant input means 
are in communication with the irrigant conduit.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings, an electrode in accordance with the 
invention comprises an elongated flexible center conductor 1 which may be 
a copper wire. The copper wire is covered by an inner insulation sleeve 3 
which extends along and fully covers the conductor. The outer diameter of 
the insulator and the wire could be of the order of 0.019 inch and the 
thickness of the inner insulator, which may be made of the material 
tefzel, could be of the order of 4.5 mil. 
Outer insulation sleeve 5 covers and extends along the inner insulation 
sleeve and leaves a gap therebetween to define an irrigant conduit. In the 
gap between the insulation sleeves is a metallic sleeve 7 which comprises 
a woven metallic braiding. Inasmuch as the braiding is woven, and 
therefore includes spaces, the braiding is porous and therefore permits 
passage of irrigant through the space between the inner and outer 
insulators. 
Extending along and covering the outer insulation sleeve 5 is a loosely 
fitting outer sheath 9. The gap 11 between the outer sheath 9 and the 
outer insulation sleeve 5 comprises a fluid conduit. 
Irrigant inlet 13 comprises an inlet to provide irrigant to the irrigant 
conduit. It includes a means 15 which is in fluid contact with the 
irrigant conduit, and a connector 17 which is connected to a source of 
irrigant. 
Fluid inlet 19 is in fluid communication with the fluid conduit. It 
includes a means 21 for effecting the fluid communication, and a connector 
23 which can be connected to a source of fluid such as air. A stop cock 24 
is provided at the end of the connector 23. 
For electrical connection, an electrical coax connector 25 is provided at 
the connector end 26 of the electrode. The coax connector, as is well 
known in the art, includes a center pin 27 and a ground connector 29. The 
ground connector is, of course, an extension of the woven metallic 
braiding 7. 
A centering means is provided at the discharge end 30 of the electrode. The 
centering means comprises a balloon 31, which may be of a latex material, 
having one end thereof attached to the outer sheath 9 and having the other 
end thereof attached to the outer insulation sleeve 5. The metallic braid 
7 is positioned over the helical coil 33 at the discharge end 30 of the 
electrode, and the helix is then covered with the outer insulation sleeve 
5. The helix 33 is provided both to provide memory at the discharge end of 
the electrode (i.e., springback) and to increase the durability thereof. 
In operation, the electrode is first inserted into the human body adjacent 
to the calculi which is to be eliminated. Irrigant can then be supplied by 
connecting connector 17 to a source of irrigant and turning the source on. 
The irrigant will exit from the electrode at the discharge end thereof. 
When the electrode is used to eliminate calculi in a duct, and it is 
desired to center the electrode in the duct, the connector 23 is connected 
to a source of fluid, for example, an air pump, and the source is turned 
on. This will cause the balloon to expand. The balloon will expand in such 
a manner that its longitudinal axis will remain coincident with the 
longitudinal axis of the electrode, i.e., it will evenly expand outwardly. 
Thus, when the balloon contacts the inner wall of a duct, the electrode 
will be centered in that duct. The stop cock is closed to prevent the air 
from escaping from the balloon after it has been inflated. Before removal 
of the electrode, the stop cock will be opened so that the air will be 
permitted to escape and the balloon will then be deflated. The air can be 
withdrawn from the balloon either by permitting it to escape naturally, or 
by applying a source of negative pressure to the connector 23. 
In accordance with a further embodiment of the invention, there is provided 
a unitary connector for both the irrigant and the fluid inlets as 
illustrated in FIG. 4. As can be seen in FIG. 4, the unitary connector 
comprises a solid block 35. A fluid inlet 37 is connected to a fluid 
channel 39 which is in fluid communication with the fluid conduit 11. In a 
like manner, an irrigant connector 41 comprises an irrigant channel 43 
which is in fluid contact with the irrigant conduit 7. In accordance with 
a further embodiment of the invention, the unitary connector will also 
include an electrical connector 45. 
Although several embodiments have been illustrated, this was for the 
purpose of describing, but not limiting, the invention. Various 
modifications, which will come readily to the mind of one skilled in the 
art, are within the scope of the invention as defined in the appended 
claims.