An apparatus for electrosurgical incision of a stricture within or adjacent to a body lumen, which comprises an electrically conducting, deflectable wire associated with an introducer for introducing the apparatus into the body lumen, wherein a proximal portion of the wire is deflectable outwardly relative to the introducer, and a source of RF electric current connected to the wire whereby RF electric current may be transmitted through the wire when it is in the deflected position.

FIELD OF THE INVENTION 
This invention relates to an electrosurgical apparatus. More particularly, 
the invention relates to an electrosurgical knife for transurethral 
incision of the prostate (TUIP), and to a method for performing TUIP using 
RF electric energy. 
BACKGROUND OF THE INVENTION 
Various instruments for performing surgical cutting operations in body 
lumens, for example, blood vessels, are known in the art. 
For example, U.S. Pat. No. 4,909,781 discloses a flexible catheter for 
opening obstructions in a blood vessel including an annular, rotatable 
cutter having a flexible coil spring body positioned at one end of a thin, 
flexible, cylindrical tube adapted for insertion in the vessel. 
U.S. Pat. No. 5,030,201 discloses an expandable atherectomy catheter device 
having an expandable cutting head consisting of deformable cutting members 
to remove an atheroma or blood clot from a blood vessel. 
U.S. Pat. No. 5,071,424 discloses a catheter atherotome comprising a 
plurality of elongate cutting blades disposed within a catheter for 
removing plaque from the interior wall of an artery. 
U.S. Pat. No. 5,074,871 discloses another form of catheter atherotome 
having an expansable cutter head at the distal end of a catheter. 
All of the above instruments utilize mechanical cutters to remove 
obstructions in blood vessels. 
It is also known to remove obstructions by electrosurgery, i.e., by the use 
of an electrode, which may or may not be in the form of a sharp blade, 
which conducts RF electrical energy. 
Thus, U.S. Pat. No. 5,057,107 discloses a RF ablation catheter for removing 
athero-stenotic lesions in blood vessels including a pair of electrodes 
which create an electric arc for effecting cutting upon application of RF 
voltage. 
U.S. Pat. No. 5,080,660 discloses an electrosurgical electrode having a 
conductor from which a RF electrical signal is generated, which conductor 
is surrounded by a sheath having a longitudinal slit to expose the 
conductor over the region where a surgical procedure is desired. 
U.S. Pat. No. 5,163,938 discloses a high-frequency electrosurgical treating 
device comprising a wire for high-frequency incision in combination with 
an endoscope. The device is typically used for papillo-sphincterotomy. 
The present invention is predicated upon the concept of using an 
electrosurgical device to perform an incision procedure on the prostate. 
Transurethral incision of the prostate (TUIP) is a less traumatic procedure 
than transurethral resection of the prostate (TURP), the most common 
operation for benign prostate hyperplasia (BPH). For selected patients 
TUIP has been found by some urologists to be as effective as TURP, with 
the advantage that it permits a shorter hospital stay and is associated 
with fewer complications and undesirable effects. 
TUIP is typically performed with a cold (unpowered) knife. It has now been 
found that the use of an electroctrosurgical (ES) knife, particularly a 
monopolar electrosurgical knife, powered by radio-frequency (RF) 
electrical energy from an electrosurgical unit (ESU) makes a cutting 
operation easier, more direct, and thus less traumatic, than cutting with 
an unpowered knife. Moreover, use of a RF powered knife permits the 
convenient application of coagulating power for hemostasis. 
However, conventional ES knives are not well adapted for TUIP. The urethra 
is an elongated, narrow tube about one centimeter in diameter, and the 
prostate extends radially outward from the urethra and needs to be incised 
to a depth of up to four centimeters. Accordingly, the instrument should 
have a configuration with a low profile for atraumatic passage through the 
urethra, but be adapted to be redeployed into a configuration appropriate 
for the TUIP procedure. An instrument which satisfies these requirements 
and also has other advantages is provided by the present invention. 
SUMMARY OF THE INVENTION 
In accordance with the present invention there is provided an apparatus for 
electrosurgical incision of a stricture within or adjacent to a body lumen 
which apparatus is elongated, has a longitudinal axis and comprises an 
electrically conducting deflectable wire associated with introducer means 
for introducing the apparatus into the body lumen, means for deflecting a 
proximal portion of the wire outwardly relative to said introducer means, 
a source of RF electric current connected to the wire and means for 
transmitting RF electric current through the wire when it is in the 
deflected position. 
As used herein the term "proximal" means the location at or near the site 
of the surgical procedure and the term "distal" means the location at or 
near the operator. 
In a preferred embodiment of the invention the introducer means is sized to 
be inserted in a urethra and the deflectable wire, when deflected, is 
sized to perform transurethral incision of the prostate or urethral 
strictures. Alternatively, the apparatus may be sized to be inserted in a 
ureter to perform incision of a ureteral stricture. 
The proximal portion of the apparatus has a low profile, which means that 
it has a configuration which is elongated and narrow enough to pass 
through a chosen body lumen without undue trauma or dilation. The 
apparatus may be substantially rigid or flexible and preferably the 
proximal end thereof is smooth and rounded to facilitate passage through 
the body lumen, for example, the urethra or ureter. 
Preferably, the introducer means comprises a nosepiece defining a conduit 
embracing at least part of a proximal portion of the deflectable wire, the 
wire being slidable within the conduit. The nosepiece preferably is made 
from an electrically insulating material, for example a moulded 
biologically compatible plastic, such as a polyurethane. 
Preferably the portion of wire deflected outwardly is in the form of a loop 
defining a monopolar electrosurgical knife, which loop terminates in two 
distal ends extending beyond the distal end of the introducer means and 
the means for deflecting the wire is by pulling one distal end and pushing 
the other distal end. In one embodiment the distal ends of the wire are 
attached to a reel and the pulling and pushing is effected by rotating the 
wheel. Also, the wire may be springwound to achieve axial stability 
(pushability). 
In a particularly preferred embodiment the wire is flat so that when it is 
deflected outwardly it bows in a predictable direction. This provides 
better directional stability. 
The wire is preferably made from a superelastic alloy, especially an alloy 
of nickel and titanium. Preferably, the deflected position is attained by 
deflecting the wire loop outwardly in a direction transverse to the 
longitudinal axis of the apparatus, and the apparatus may include means 
for controlling the degree of deflection of the wire loop. 
Also the loop may include a pointed member, for example a needle, the 
combination of loop and needle defining a monopolar electrosurgical knife. 
In a particularly preferred embodiment of the invention the catheter is 
accommodated within a cystourethroscope or a small flexible urethroscope 
so that the apparatus may be used under endoscopic vision. The 
urethroscope may be a conventional resectoscope. 
When the apparatus is sized to perform incision of ureteral strictures it 
may be accommodated within a ureteroscope. 
The invention also provides a method for performing transurethral incision 
of the prostate of a patient or incision of a ureteral stricture in a 
patient which comprises inserting an apparatus as described above in the 
urethra or ureter of the patient until the deflectable wire is located in 
a position to perform the desired incision, deflecting the wire outwardly 
to assume a cutting configuration, applying RF electric current through 
the wire while moving the apparatus to perform the desired incision, 
switching off the current when the incision procedure is completed, 
retracting the wire within the apparatus and withdrawing the apparatus 
from the urethra or ureter. 
DETAILED DESCRIPTION OF THE INVENTION 
The apparatus according to the invention has an initial low profile 
configuration which enables it to be inserted into and passed along a body 
lumen, for example a urethra or ureter, with the minimum discomfort and 
trauma. This makes it particularly suitable for the performance of TUIP or 
for the incision of strictures in the urethra or ureter. The invention 
will be more particularly described with reference to the preferred use as 
an electrosurgical knife for the performance of TUIP. 
A problem associated with prior instruments for TUIP arises from the fact 
that they are usually inserted through a channel of a rigid 
cystourethroscope. The size and rigidity of such an instrument makes the 
procedure painful. The apparatus of the present invention is sized to be 
used advantageously with a small flexible urethroscope, thereby reducing 
anesthesia requirements to topical or regional anesthetic agents and 
consequently reducing the need for support facilities, lengthy hospital 
confinement and cost. Of course, this does not mean that the greater 
stability provided by a rigid cystourethroscope need be totally discarded, 
and in one of the embodiments described herein a rigid resectoscope is 
used. 
The apparatus of the present invention is adapted to perform TUIP with 
monopolar electrosurgical power. The wire which conveys RF electric 
current and defines the active electrode or electrosurgical knife is 
associated with introducer means so that the combination of active 
electrode and introducer provides a flexible or rigid elongated instrument 
sized to be inserted into a patient's urethra with minimum trauma or 
discomfort. During insertion the wire is contained within an appropriate 
low profile envelope, for example, a nosepiece as hereinafter described. 
When the apparatus is inserted into a patient's urethra and the operator 
is ready to perform the incision procedure a control mechanism is 
activated to deflect the wire, i.e., to cause the cutting electrode to 
assume its operating configuration. The activation may be accomplished in 
any one of several ways, for example:(i) 
(i) a control wire that is pulled to cause the deflectable wire (electrode) 
to bow outward; 
(ii) two control wires that, when one is pushed and the other pulled, cause 
the electrode to deflect outwardly from the side of the nosepiece; 
(iii) either of the above associated with a reel that, when rotated, pushes 
and/or pulls the control wire or wires; 
(iv) an elastic or superelastic electrode that is contained within a 
tubular envelope for deployment and bends upward at the proximal end when 
it is advanced out of the tube; and 
(v) the electrode carried on an elastic or superelastic non-conducting 
substrate contained within a tubular sheath for deployment which bends 
upward at the proximal end when advanced out of the tube and the electrode 
assumes the same shape as the bent substrate. 
When the apparatus of the invention is used as a monopolar electrosurgical 
knife, the deflectable wire acts as the active electrode when activated by 
RF electrical current and the circuit is completed by a return electrode 
attached to the patient's body in a manner known in the art.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1 and FIG. 2 illustrate the proximal portion of an apparatus 
comprising a deflectable electrically conducting wire 1 which defines a 
loop 2 at the proximal end of the apparatus and two limbs 3,4 extending 
toward the distal end of the apparatus. For most of its length the wire 
has an electrically insulating coating or sheath 5, and only the portion 
to be deflected and form the cutting electrode is exposed. The proximal 
portion of the wire is enveloped in a sheath 6, preferably made of a 
smooth, biocompatible plastic, preferably a polyurethane or polyethylene, 
having a rounded smooth proximal end 7, which sheath acts as an introducer 
when the wire is undeflected and contained therein (FIG. 1 ). The 
introducer is elongated and has a longitudinal axis and a slot adjacent 
the proximal end through which the wire may be deflected outwardly in a 
direction transverse to the longitudinal axis to provide the cutting 
configuration (FIG. 2). 
As illustrated in FIG. 1, the introducer has a low profile which enables 
the apparatus to be inserted in a body lumen, for example a urethra or 
ureter, with minimum trauma. When the apparatus is properly positioned 
within the urethra, the distal end 4 of the wire is pulled to deflect the 
exposed proximal portion of the wire outwardly in a direction transverse 
to the longitudinal axis of the apparatus as shown in FIG. 2. In this 
embodiment the limb 3 remains fixed. In the preferred embodiment where the 
wire is flat, as shown in FIG. 2A, the wire bows outwardly without kinking 
or distortion. 
FIG. 3 and FIG. 4 illustrate another embodiment, similar in many respects 
to the embodiment of FIG. 1 but wherein the distal ends 3' and 4' are both 
movable to deflect the electrode wire 1 and the desired deflection of the 
wire is achieved by pushing the distal end 3' and pulling the distal end 
4'. In a preferred embodiment, illustrated in FIG. 5, the distal ends of 
the wire 3', 4' are attached to a reel 8. One of the ends 3' is wound 
around the core of the reel in a counterclockwise direction and the other 
end 4' is wound around the core in a clockwise direction. Thus, when the 
reel is rotated in a clockwise direction, as indicated by the arrow, the 
wire 4' is pulled and the wire 3' is pushed, whereby the proximal end of 
the wire is deflected outwardly. When the reel is rotated counterclockwise 
the wires are moved in the opposite direction and the wire is returned to 
the withdrawal configuration. 
In the apparatus illustrated in FIGS. 1, 2, 3, 4 and 5 the deflected wire 
is the active electrode in a monopolar electrosurgical cutting knife. The 
knife is activated by RF electrical current from a standard 
electrosurgical unit (ESU) connected to the distal end of the wire in a 
conventional way (connection not shown). The circuit is completed through 
a return electrode attached to the body of the patient in a conventional 
manner (not shown). 
FIG. 6 and FIG. 7 illustrate a preferred embodiment, particularly suitable 
for TUIP. FIG. 6 shows the instrument in the insertion-withdrawal 
configuration and FIG. 7 shows the wire deflected in the cutting 
configuration. The instrument is adapted to be held in the working element 
of a resectoscope as described hereinafter with reference to FIG. 8. 
The TUIP instrument illustrated in FIG. 6 comprises a conductor-carrying 
tube 9 (identified herein for convenience only as the "hot tube"), which 
tube contains a flat profile deflectable wire 15 capable of carrying RF 
electrical current. RF current from an electrosurgical unit (ESU), not 
shown, enters the hot tube through a contact 1 0, which is insulated from 
the exterior of the tube. A notch 11 adjacent the distal end of the tube 
enables the tube to be held in the working element of a resectoscope and 
the tube is aligned to the axis of the resectoscope by guides 12 and 13. 
The proximal end of the hot tube is associated with introducer means which 
includes a nosepiece 14 defining a conduit 16 through which the hot tube 
passes. The nosepiece is made from an electrically insulating polymer, 
preferably a moulded polyurethane. The diameter of the conduit determines 
the friction between the hot tube and the nosepiece and thus controls the 
ease with which the hot tube may slide axially. The sliding motion is what 
raises and lowers the cutting electrode. A small key 17 prevents rotation 
of the hot tube within the nosepiece. 
The hot tube extends proximally beyond the nosepiece about 0.7 Inch. The 
insulated cutting electrode wire 18 emerges from the end of the hot tube 
and makes a hairpin bend before passing through a backing tube 19. A 
pointed member, preferably a needle 20, extends about 0.1 Inch from the 
proximal end of the backing tube. The outside of the backing tube is 
insulated, but the needle is uninsulated and forms part of the cutting 
electrode. The uninsulated electrode wire 15 with the needle emerges from 
the proximal end of the backing tube and continues, in a deflected 
configuration (FIG. 7), to an anchoring point 21 on the nosepiece. The 
wire is anchored by being passed around a screw 22 within the nosepiece, 
as shown in FIG. 6A. When the desired length of wire has been taken up the 
screw is heated to its softening point. As the screw cools it bonds to the 
nosepiece and attachment of the wire is secured. FIG. 6A also shows hot 
tube 9, electrode wire 15 with its insulation 23, and key 17. Preferably 
the electrode wire is high temper 304 stainless steel ribbon wire, 
insulated by polytetrafluoroethylene shrink tubing. Preferably, the hot 
tube, cold rod 24, telescope guides 12, 13, backing tube 19, and needle 20 
are made from 304 stainless steel. 
The cold rod or push rod 24 is the means for holding the nosepiece immobile 
when changing the configuration of the cutting assembly and it may be a 
hollow tube or a solid rod. The proximal end of the cold rod is inserted 
into a hole in the nosepiece and is rigidly attached by a transverse pin 
25. Thus, motion of the hot tube 9 relative to the cold rod 24 changes the 
configuration of the cutting assembly. If the cold rod and hot tube are 
moved together, the entire instrument moves axially without changing its 
configuration. The guides 12 and 13 are rigidly attached to the cold rod 
by attachments 26, but slidably attached to the hot tube by attachments 27 
(FIG. 6B). 
A notch 39 adjacent the distal end of the cold rod is adapted to accept a 
clip 41 (FIG. 10) to prevent movement of the cold rod in a proximal 
direction. A collar 40 welded to the cold rod acts as a stop in the distal 
direction (FIG. 9). 
When the hot tube is pulled in a distal direction while the nosepiece is 
held immobile the distance the hot tube extends out of the nosepiece is 
decreased, leaving a shorter distance between the wire's emergence from 
the tube and its anchoring point. The cutting assembly comprising 
uninsulated portion 15 of the electrode wire and the part of the needle 20 
that extends from the backing tube 19, therefore assumes the cutting 
configuration as shown in FIG. 7. When the hot tube is pushed in a 
proximal direction the electrode wire is stretched out and resumes the 
insertion-withdrawal configuration shown in FIG. 6. A flange 28 near the 
proximal end of the nosepiece is provided to keep the portion of the 
instrument near the needle 20 away from the wall of a delivery sheath 
described hereinafter with reference to FIG. 11. 
The mounting of a TUIP instrument according to the invention in a common 
type of resectoscope is illustrated in FIG. 8. The operation of the 
working element of the resectoscope involves motion of a distal piece 29, 
which slides along a tube 30 in response to a manual force exerted at 
thumb loop 31. A proximal piece 32 of the working element is held 
stationary by manual force exerted on a finger loop 33. The hot tube 9 of 
the TUIP instrument is securely held within the distal piece 29 by a knife 
edge 34 which engages the notch 11 and is supplied, through contact 10, 
with RF electrical current from the ESU via cable 35. A telescope 36, used 
for viewing the interior of the urethra and bladder through eyepiece 37 is 
immobile with respect to proximal piece 32. The motion of the working 
element is assisted by a spring loaded pivot 38. 
FIG. 9 and FIG. 10 illustrate the operation of the system. The hot tube 9 
and cold rod 24 slide freely through conduits in proximal piece 32. The 
hot tube 9 is attached to the distal piece 29 by the knife edge 34 which 
engages the notch 11, and receives RF current through contact 10. Motion 
of the distal piece will cause corresponding motion of the hot tube. In 
the situation shown in FIG. 9, this motion will cause axial motion of the 
entire TUIP instrument, because friction between the hot tube and the 
nosepiece is sufficient to prevent change in the configuration of the 
instrument. However, in the situation shown in FIG. 10, a clip 41 is 
placed in notch 39. Since the clip is too large to pass through the 
conduit in proximal piece 32, the cold rod can not move in a proximal 
direction. Since the collar 40, welded to the cold rod, prevents the cold 
rod from moving in a distal direction, the cold rod is immobile with 
respect to proximal piece 32. In this situation the nosepiece is similarly 
immobile with respect to proximal piece 32. Accordingly, motion of distal 
piece 29 in a proximal direction has the effect of moving the cutting 
assembly to the insertion-withdrawal configuration, while motion of the 
distal piece in a distal direction moves the cutting assembly to the 
cutting configuration. Thus, with clip 41 in place, movement of the distal 
piece changes the configuration of the TUIP instrument, while without the 
clip, movement of the distal piece moves the entire instrument axially 
without changing the configuration. 
A preferred assembly containing the TUIP instrument for a surgical 
procedure is illustrated in FIG. 11. The operating surgeon inserts a metal 
sheath 42 in a patient's urethra. A spacer 43 may be attached to the 
distal piece of the working element to limit its travel, which has the 
effect, as described hereinafter, of allowing the surgeon to raise the 
cutting assembly to any desired height less than or equal to the maximum. 
The sheath 42 is a hollow tube with a lumen having a diameter large enough 
to accommodate the viewing telescope and the TUIP instrument. Initially, a 
viewing telescope is passed through the sheath to permit inspection of the 
urethra, prostate and bladder. When the surgeon is ready, the proximal 
piece 32 of the resectoscope's working element is attached to the sheath. 
As shown in FIG. 9, both the cold rod 24 and the hot tube 9 are passed 
through conduits in the proximal piece 32. Clip 41 is placed within the 
notch 39 of the cold rod. The instrument is typically in the relaxed 
position shown in FIG. 12A. This position minimizes strain on the 
instrument during storage, but is not adapted either for 
insertion-withdrawal or for surgery. In the next step the distal piece 29 
is moved forward so that the knife edge 34 engages the notch 11 of the hot 
tube 9. In this position, the hot tube can receive RF current through 
contact 10. As shown in FIG. 12B, distal piece 29 is then moved as far as 
possible in the proximal direction, thus moving the cutting assembly to 
the insertion-withdrawal configuration. This is the configuration in which 
the tuip instrument has the lowest profile and therefore passes most 
easily through sheath 42. The instrument may be passed through the sheath 
42 to the prostatic urethra. 
To perform incision of the prostrate, the surgeon moves the cutting 
assembly to the cutting configuration by drawing back the distal piece 29 
by means of manual force at thumb loop 31. The cutting configuration is 
shown in FIG. 12C. The surgeon then advances the elevated cutting assembly 
to its most proximal position by pushing forward on thumb loop 31. A 
commercially available ESU supplies RF current to the hot tube 9 through 
cable 35 and contact 10. In a typical operation, the esu would provide 
about 140 watts power at a potential of about 200 volts and a frequency of 
about 750 kilohertz to drive a current of about 0.7 Ampere. To perform the 
incision, the surgeon moves the electrode wire through tissue in a distal 
direction by drawing back on thumb loop 31 while applying RF current from 
the ESU. The needle 20, acts as a hook to facilitate attachment and 
movement of the cutting edge through the tissue. Since the clip 41 has 
been removed, the entire instrument moves as a unit as described above. 
Typically the application of power is controlled by a footswitch operated 
by the surgeon, and power is applied only when the instrument is being 
moved in a distal direction. 
In a preferred embodiment means is provided for controlling the degree of 
deflection of the wire loop. Thus, use of the spacer 43, as shown in FIG. 
11, decreases the distance by which the distal piece 29 may be drawn back, 
with the result, shown in FIG. 12D, that the cutting assembly is elevated 
to a height less than that achieved without the spacer. This is useful if 
an incision of smaller depth is desired. The instrument will normally be 
supplied with several marked spacers of different thicknesses for 
achieving various heights as desired by the surgeon. 
When the desired incision is made, the thumb loop is again drawn back as 
far as possible, and the clip 41 is placed in the notch 39. The thumb loop 
is then moved in the proximal direction as far as it will go, causing the 
cutting assembly to assume the insertion-withdrawal configuration. The 
instrument is then withdrawn from the sheath. The flange 28 pushes the 
part of the instrument nearest the needle 20 away from the wall of the 
sheath, thus avoiding the danger that the needle will snag the sheath and 
prevent smooth withdrawal of the instrument. 
The use of an apparatus according to the invention in a procedure as 
described herein provides a safe and efficacious way of performing a TUIP 
operation or incision of a ureteral stricture.