Ablative catheter with conformable body

A medical probe device for reducing tissue mass in a selected portion of the body comprises a catheter having a control end and a probe end. The probe end includes a malleable tube and a flexible tube that allow the probe end to conform to the curvature of the cavity inside a patient's body.

FIELD OF THE INVENTION 
This invention is directed to a unique device for penetrating body tissues 
for medical purposes, such as reducing the mass of selected tissues by 
therapeutic ablation and fluid substance delivery. The device penetrates 
tissue to the precise target selected in order to deliver energy to the 
tissue and/or deliver substances. The penetrating portion is flexible 
enough to accommodate any curve within the cavity of the body. It limits 
this treatment to the precise preselected site, thereby minimizing trauma 
to normal surrounding tissue and achieving a greater medical benefit. This 
device includes a catheter for positioning a treatment assembly in the 
area or organ selected for medical treatment and one or more stylets which 
are mounted for extension from a stylet port in the side of the catheter 
through surrounding tissue to the tissue targeted for medical 
intervention. 
BACKGROUND OF THE INVENTION 
Treatment of cellular tissues usually requires direct contact of target 
tissue with a medical instrument, usually by surgical procedures exposing 
both the target and intervening tissue to substantial trauma. Often, 
precise placement of a treatment probe is difficult because of the 
location of targeted tissues in the body or the proximity of the target 
tissue to easily damaged, critical body organs, nerves, or other 
components. 
Benign prostatic hypertrophy or hyperplasia (BPH), for example, is one of 
the most common medical problems experienced by men over 50 years old. 
Urinary tract obstruction due to prostatic hyperplasia has been recognized 
since the earliest days of medicine. Hyperplastic enlargement of the 
prostate gland often leads to compression of the urethra, resulting in 
obstruction of the urinary tract and the subsequent development of 
symptoms that include frequent urination, decrease in urinary flow, 
nocturia, pain, discomfort, and dribbling. The association of BPH with 
aging has been shown to exceed 50% in men over 50 years of age and 
increases in incidence to over 75% in men over 80 years of age. Symptoms 
of urinary obstruction occur most frequently between the ages of 65 and 
70, when approximately 65% of men in this age group have prostatic 
enlargement. 
Currently, there is no proven effective nonsurgical method of treatment of 
BPH. In addition, the surgical procedures available are not totally 
satisfactory. Currently, patients suffering from the obstructive symptoms 
of this disease are provided with few options: continue to cope with the 
symptoms (i.e., conservative management), submit to drug therapy at early 
stages, or submit to surgical intervention. More than 430,000 patients per 
year undergo surgery for removal of prostatic tissue in the United States. 
These represent less than five percent of men exhibiting clinically 
significant symptoms. 
Those suffering from BPH are often elderly men, many with additional health 
problems that increase the risk of surgical procedures. Current surgical 
procedures for the removal of prostatic tissue are associated with a 
number of hazards, including anesthesia related morbidity, hemorrhage, 
coagulopathies, pulmonary emboli and electrolyte imbalances. These current 
procedures can also lead to cardiac complications, bladder perforation, 
incontinence, infection, urethral or bladder neck stricture, retention of 
prostatic chips, retrograde ejaculation, and infertility. Due to the 
extensive invasive nature of the current treatment options for obstructive 
uropathy, the majority of patients delay definitive treatment of their 
condition. This circumstance can lead to serious damage to structures 
secondary to the obstructive lesion in the prostate (bladder hypertrophy, 
hydronephrosis, dilation of the kidney pelves, chronic infection, dilation 
of ureters, etc.), which is not without significant consequences. In 
addition, a significant number of patients with symptoms sufficiently 
severe to warrant surgical intervention are therefore poor operative risks 
and are poor candidates for prostatectomy. In addition, younger men 
suffering from BPH who do not desire to risk complications, such as 
infertility, are often forced to avoid surgical intervention. Thus the 
need, importance and value of improved surgical and non-surgical methods 
for treating BPH is unquestionable. 
High-frequency currents are used in electrocautery procedures for cutting 
human tissue, especially when a bloodless incision is desired or when the 
operating site is not accessible with a normal scalpel but presents an 
access for a thin instrument through natural body openings, such as the 
esophagus, intestines or urethra. Examples include the removal of 
prostatic adenomas, bladder tumors or intestinal polyps. In such cases, 
the high-frequency current is fed by a surgical probe into the tissue to 
be cut. The resulting dissipated heat causes boiling and vaporization of 
the cell fluid, whereupon the cell walls rupture and the tissue is 
separated. 
Destruction of cellular tissues in situ has been used in the treatment of 
many diseases and medical conditions alone or as an adjunct to surgical 
removal procedures. It is often less traumatic than surgical procedures 
and may be the only alternative where other procedures are unsafe. 
Ablative treatment devices have the advantage of using electromagnetic 
energy that is rapidly dissipated and reduced to a non-destructive level 
by conduction and convection forces of circulating fluids and other 
natural body processes. 
Microwave, radiofrequency, acoustical (ultrasound) and light energy (laser) 
devices, as well as tissue destructive substances, have been used to 
destroy malignant, benign and other types of cells and tissues from a wide 
variety of anatomic sites and organs. Tissues treated include isolated 
carcinoma masses and, more specifically, organs such as the prostate, 
glandular and stromal nodules characteristic of benign prostate 
hyperplasia. These devices typically include a catheter or cannula which 
is used to carry a radiofrequency electrode or microwave antenna through a 
duct to the zone of treatment and apply energy diffusely through the duct 
wall into the surrounding tissue in all directions. Severe trauma is often 
sustained by the duct wall during this cellular destruction process, and 
some devices combine cooling systems with microwave antennas to reduce 
trauma to the ductal wall. For treating the prostate with these devices, 
for example, heat energy is delivered through the walls of the urethra 
into the surrounding prostate cells in an effort to ablate the tissue 
causing the constriction of the urethra. Light energy, typically from a 
laser, is delivered to prostate tissue target sites by "burning through" 
the wall of the urethra. Healthy cells of the duct wall and healthy tissue 
between the nodules and duct wall are also indiscriminately destroyed in 
the process and can cause unnecessary loss of some prostate function. 
Furthermore, the added cooling function of some microwave devices 
complicates the apparatus and requires that the device be sufficiently 
large to accommodate this cooling system. 
Application of liquids to specific tissues for medical purposes is limited 
by the ability to obtain delivery without traumatizing intervening tissue 
and to effect a delivery limited to the specific target tissue. Localized 
chemotherapy, drug infusions, collagen injections, or injections of agents 
that are then activated by light, heat or chemicals would be greatly 
facilitated by a device that could conveniently and precisely place a 
fluid (liquid or gas) supply cannula opening at the specific target 
tissue. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of this invention to provide a device for penetrating 
tissue, through intervening tissues to the precise target tissue selected 
for a medical action, such as tissue ablation and/or substance delivery, 
limiting this activity to the precise preselected site, and thereby 
minimizing the trauma and achieving a greater medical benefit. 
It is further an object of this invention to provide a device with a 
flexible intruding portion for tissue ablation of body tissues which 
delivers the therapeutic energy directly into targeted tissues while 
minimizing effects on its surrounding tissue. 
It is another object of this invention to provide a device whereby its 
intruding portion is flexible enough to accommodate any curves or 
obstructions within a body cavity being penetrated. 
In summary, the medical probe device for reducing tissue mass in a selected 
portion of the body includes a catheter having a control end and a probe 
end. The probe end comprises a tip having at least one stylet port. The 
probe end further comprises a conforming means attached between the 
control end and the tip for directing a flexible styler outward through 
the stylet port while negotiating curvatures inside a human cavity. A 
flexible stylet which includes a non-conductive sleeve having an electrode 
lumen and a second lumen therein is positioned in the probe end. The 
electrode lumen terminates at a distal port in the distal end of the 
non-conductive sleeve. A radiofrequency electrode is being positioned in 
the electrode lumen for longitudinal movement therein and through the 
distal port. 
In one embodiment of this invention, the conforming means includes a 
malleable tube attached to a flexible tube. 
In another embodiment of this invention, the conforming means includes a 
malleable tube. 
The medical probe device is particularly useful for removing tissue mass 
from the prostate and can be used for treating BPH or benign or cancerous 
tumors of the prostate. 
The device of this invention can be used in combination with a viewing 
scope, such as a cystoscope, endoscope, laproscope and the like, which is 
sized to extend therethrough. 
Alternatively, the device can include a viewing scope, a fiber optic 
enclosed within the catheter and optic viewing means at the control end 
which is connected to the fiber optic.

DETAILED DESCRIPTION OF THE INVENTION 
The device of this invention provides a precisely controlled positioning of 
a treatment styler in a tissue targeted for treatment, destruction or 
sampling from a catheter positioned in the vicinity of the target tissue. 
This is described in U.S. Pat. Nos. 5,366,490 and 5,370,675 the entire 
contents of which are incorporated herein by reference. The device of the 
present invention further provides a catheter that is capable of 
conforming to curvatures within a body cavity. 
The term "stylet" as used hereinafter is defined to include both solid and 
hollow probes which are adapted to be passed from a cannula port through 
normal tissue to targeted tissues. The stylet is shaped to facilitate easy 
passage through tissue. It can be a solid wire, thin rod, or other solid 
shape or it can be a thin hollow tube or other shape having a longitudinal 
lumen for introducing fluids to or removing materials from a site. The 
stylet can also be a thin hollow tube or other hollow shape, the hollow 
lumen thereof containing a reinforcing or functional rod or tube, such as 
a laser fiber optic. The stylet preferably has a sharpened end to reduce 
resistance and trauma when it is pushed through tissue to a target site. 
The stylet can be designed to provide a variety of medically desired 
treatments of a selected tissue. As a radiofrequency electrode or 
microwave antenna, it can be used to ablate or destroy targeted tissues. 
As a hollow tube, it can be used to deliver a treatment fluid such as a 
liquid to targeted tissues. The liquid can be a simple solution or a 
suspension of solids, for example, colloidal particles, in a liquid. Since 
the stylet is very thin, it can be directed from the cannula through 
intervening normal tissue with a minimum of trauma to the normal tissue. 
The device of this invention provides a more precise, controlled medical 
treatment which is suitable for destroying cells of medically targeted 
tissues throughout the body, both within and external to body organs. The 
device is particularly useful for treating benign prostate hyperplasia 
(BPH), and the device and its use are hereinafter described with respect 
to BPH, for purposes of simplifying the description thereof. It will be 
readily apparent to a person skilled in the art that the device can be 
used to destroy body tissues in any body cavities or tissue locations that 
are accessible by percutaneous or endoscopic catheters, and is not limited 
to the prostate. Application of the device in all of these organs and 
tissues is intended to be included within the scope of this invention. 
BPH is a condition that arises from the replication and growth of cells in 
the prostate and the decrease of cell death rate, forming glandular and 
stromal nodules which expand the prostate and constrict the opening of the 
prostatic urethra. Glandular nodules are primarily concentrated within the 
transition zone, and stromal nodules within the periurethral region. 
Traditional treatments of this condition have included surgical removal of 
the entire prostate gland, digital removal of the adenoma, as well as 
transurethral resection of the urethral canal and prostate to remove 
tissue and widen the passageway. One significant and serious complication 
associated with these procedures is iatrogenic sterility. More recently, 
laser treatment has been employed to remove tissue, limiting bleeding and 
loss of body fluids. Balloons have also been expanded within the urethra 
to enlarge its diameter, with and without heat, but have been found to 
have significant limitations. 
Microwave therapy has been utilized with some success by positioning a 
microwave antenna within the prostatic urethra and generating heat in the 
tissue surrounding the urethra with an electromagnetic field. Coolants are 
sometimes applied within the catheter shaft to reduce the temperature of 
the urethral wall. This necessitates complicated mechanisms to provide 
both cooling of the immediately adjacent tissues while generating heat in 
the more distant prostatic tissue. This technique is similar to microwave 
hyperthermia. Similarly, radiofrequency tissue ablation with electrodes 
positioned within the urethra exposes the urethral wall to destructive 
temperatures. To avoid this, low temperature settings required to protect 
the urethra must be so low that the treatment time required to produce any 
useful effect is unduly extended, e.g. up to three hours of energy 
application. 
The device of this invention accesses the prostate through the urethra and 
positions RF electrode stylets directly into the tissues to be destroyed. 
The portion of the stylet conductor extending from the urethra to targeted 
tissues is enclosed within a longitudinally adjustable sleeve shield which 
prevents exposure of the tissue adjacent to the sleeve to the RF current. 
The sleeve movement controls the amount of electrode exposed, which is 
used to control the amount of energy per unit surface area that is 
delivered to the target tissue. Thus, the ablative destruction is confined 
to the tissues targeted for destruction, namely those causing the 
constriction. Other aspects of the invention will become apparent from the 
drawings and accompanying descriptions of the device of this invention. It 
will be readily apparent to a person skilled in the art that this 
procedure can be used in many areas of the body for percutaneous 
approaches and approaches through body orifices. 
Further details about the preferred embodiments of the invention will 
become evident in conjunction with the description of the drawings. 
FIG. 1 shows a medical device 10 according to the present invention. The 
medical device 10 includes a catheter 14 connected to a control unit 12 by 
means of a connector 16. A tip 18 is connected to the distal end of the 
catheter 14. Tip 18 includes at least one port 20 which allows the stylet 
to protrude and contact the target issue. 
FIG. 2 is a top plan view, partially cut away view of catheter 14. It shows 
the specific parts of a typical example of catheter 14. Catheter 14 
includes steel tube 30, flexible tube 32 which is connected to the distal 
end of steel tube 30, malleable tube 34 which is connected to the distal 
end of flexible tube 32, and a polymeric outer layer 36. Catheter 14 
further includes tip 18, stylet ports 38 and 40, and electrodes 42 and 44. 
As disclosed in the above-mentioned co-pending applications, catheter 14 
includes tubings (not shown) which allow the stylets to be extended inside 
the patient's body. The stylets include a flexible sleeve 43 which enclose 
radiofrequency ("RF") electrodes. RF electrodes 42 and 44 are used to 
deliver the ablative energy to the target tissue. The electrodes are 
extended outward through ports 38 and 40 to contact the selected tissues. 
Although two ports are shown in FIG. 2, catheter 14 could have one port or 
more than two ports. The number of electrodes is preferably the same as 
the number of ports. 
As previously mentioned, existing catheters are not easily bendable to 
provide easier insertion into a body cavity. This forces the body to 
continuously adjust to allow the catheter to be extended toward a target 
tissue. The present invention provides a catheter that is easily bendable 
for easier insertion into the body cavity. 
The above capability facilitates insertion of the catheter by the 
physician. The flexibility present in catheter 14 of the present invention 
prevents unnecessary trauma to the patient's body. The overall flexibility 
of the catheter of the present invention is provided by two separate 
sections. Flexible tube 32 provides the capability of flexure after it is 
inserted inside the cavity. Malleable tube 34 provides the capability of 
changing the orientation of catheter 14 before it is inserted inside the 
cavity. The change in the orientation is permanent until the user changes 
the orientation of catheter 14. 
Depending on the requirement of catheter 14, malleable tube 34 could have 
different paths or lumens for routing stylers or probes through the 
catheter. FIG. 3 is a cross-sectional view of an example of malleable tube 
34 in FIG. 2, showing different lumens provided therein. FIG. 4 is a 
cross-sectional view of the malleable tube shown in FIG. 3 taken along the 
line 4--4 of FIG. 3. Malleable tube 34 includes a cylindrical housing 510 
optical path or lumen 52, and stylet paths or lumens 54. Malleable tube 34 
also includes mating surfaces 56 and 58. Although, two stylet paths 54 are 
shown in FIG. 4, the present invention could include only one stylet path 
or more than two stylet paths. The choice of the number of stylet paths 
depends on the specific requirements of the medical device 10. 
For malleable tube 34 to be easily bendable, it must be made of materials 
that are easily deformed such as copper or equivalent malleable metal or 
plastic. 
As shown in FIG. 3, malleable tube 34 includes mating surfaces 56 and 58. 
They are provided to facilitate the connection between the two adjacent 
tubes, for example, malleable tube 34 and flexible tube 32. The detail 
description of different methods of connecting the two adjacent tubes will 
be explained hereinafter. 
As described above, slotted flexible tube 32 provides the capability of 
flexing catheter 14 while it is inside a body cavity. Suitable slotted 
tubes and methods for their manufacture are described in U.S. Pat. Nos. 
4,642,098, 5,195,968, 5,228,441, 5,243,167, 5,315,996 and 5,322,064, the 
entire contents of which are hereby incorporated by reference. 
FIG. 5 is another embodiment of flexible tube 32. Flexible tube 32 includes 
a solid tube section 70 and flexible tube section 72 having flexible 
portions spaced apart longitudinally between its proximal and distal ends 
86 and 88. Each flexible portion 74, 76, 78, 80, 82 and 84 includes a 
slotted section 90 and a solid section 92. The length of slotted section 
90 and solid section 92 of each flexible portion depends on the 
requirement of the flexible tube 32. Furthermore, the length of slotted 
section 90 and solid section 92 can differ from one flexible portion to 
the next. 
FIG. 6 is an enlarged view of a typical slotted section 90. Each slotted 
section 90 includes at least one and preferably more than one short 
cylinder 100. Each short cylinder 100 includes a radial slot 102 
positioned between its two ends. The width of each radial slot 102 depends 
on the requirement of the catheter. Radial slot 102 subtends less than one 
circumference of short cylinder 102 wall, or in other words less than 
360.degree.. 
In order to obtain flexibility in all directions, the open end of radial 
slot 102 of different slotted section 92 must be aligned at different 
angles, For example, in FIG. 6, the open ends of radial slots 102 are 
aligned such that an axis through the slots is perpendicular to the 
longitudinal axis of flexible tube 32. The open ends of slots of the 
slotted section in the next flexible portion could be provided at a 
60.degree. angle with respect to the longitudinal axis of flexible tube 
32. 
The desired degree of flexibility in a flexible portion can be varied by 
providing fewer or more slots 102 in that flexible portion. Thus, there 
can be provided as few as a single slot to a total of 10 or more slots. 
For example, the slotted section of flexible portion 84 could have 15 
slots, the slotted section of flexible portion 82 could have 15 slots, the 
slotted section of flexible portion 80 could have 20 slots, the slotted 
section of flexible portion 78 could have 23 slots, and the slotted 
section flexible portion 76 could have 20 slots and the slotted section of 
flexible portion 74 could have 15 slots. The width of each slot of a 
particular flexible tube depends on the requirement of the catheter using 
the flexible tube 32. For example, each slot in flexible portion 84 is 
0.040 inches wide. 
In the present invention, flexible tube 32 is preferably made of stainless 
steel, or other metal or plastic materials having the same 
characteristics. 
Referring to FIG. 2, thin polymeric coating or film layer 36 encapsulates 
the outer surface of catheter 14. Coating 36 is very flexible and permits 
desired flexing of the flexible tube 32 and malleable tube 34. In the case 
of flexible tube 32, coating 36 prevents undue bending or stress in the 
material of the side wall in any one slot and thereby prevents the 
placement of a permanent strain in any portion of the tube. In other 
words, the coating 36 prevents bending or flexing of flexible tube 32 
beyond the point from which it will not return to its original 
configuration. Coating 36 also serves to prevent blood or any other liquid 
in the cavity in which the catheter is introduced from entering into slots 
102 and caused possible clotting. 
The coating or film layer 36 can be formed by applying a polymeric 
film-forming solution to the surface of the catheter. Alternatively, the 
catheter can be enclosed in a thin, shrinkable tubing which is shrunk As 
seen in FIG. 6, short cylinders 100 of each flexible portion are not 
attached to the respective solid portions 92. Coating 36 also provides the 
means to align all the pieces of flexible tubes and keep them intact. 
Similar to malleable tube 34, flexible tube 32 may include an optical path 
or lumen and/or stylet paths. The availability of any or all of the above 
paths depends on the design of the catheter 14. FIG. 7 is an end view of 
flexible tube 32 which shows an example of the paths provided inside 
flexible tube 32. In the example of FIG. 7, flexible tube 32 includes an 
optical lumen or path 110 and stylet paths or lumens 112. 
FIG. 8 is a cross-sectional view taken along the longitudinal axis of 
catheter 14 (FIG. 2) showing the junctions between adjacent tube sections 
of stainless steel or equivalent metal or plastic. Tubes 120 and 122 can 
be any one of different tube sections used to form catheter 14 (FIG. 2) 
and, for example, can include surfaces such as mating surfaces 58 and 122 
shown in FIG. 3. Both mating surfaces 124 and 126 are complementary. Each 
one of the tubes 120 or 122 includes a mating surface 124 along 
180.degree. of the tube wall and a mating surface 126 along the opposite 
180.degree. of the other tube wall. This allows the particular tube to be 
able to connect to the adjacent tubes on either of its two sides. 
To connect tubes 120 and 122, they are joined such that surface 124 mates 
with surface 126. The connection between two adjacent tubes is sealed 
using any one of the readily available sealing methods. For example, epoxy 
resin adhesive could be used to seal the connection between tubes 120 and 
122. In this method, epoxy resin is applied to two mating surfaces. 
Thereafter, it is cured to create a bending between the two mating 
surfaces. An alternative method is to solder the connection between the 
two mating surfaces 124 and 126. 
FIG. 9 shows an alternative tube joinder method wherein an inner tube 
section 128 made of urethane plastic or the like presses outward against 
the inner surface of the adjacent tubes 120 and 122, clamping the tubes 
together. 
The flexible and malleable tube sections 34 and 36 shown in FIG. 2 can be 
used together or alone. FIG. 10 is a top plan view, partially cut away, of 
a catheter 140 which only incorporates a malleable tube. Catheter 140 
includes steel tube 142, malleable tube 144 which is connected to the 
distal end of steel tube 142, and coating 146. Catheter 140 further 
includes tip 148, ports 150 and 152, and electrodes 154 and 156. Catheter 
140 enables the user to deform its orientation before inserting it inside 
a body cavity. However, once inside the cavity, it does not have 
flexibility to accommodate incidental curvatures. 
FIG. 11 is a top plan view, partially cut away, of a catheter 170 which 
includes flexible tube 174 as part of its structure. Catheter 170 includes 
steel tube 172, flexible tube 174 which is connected to the distal end of 
steel tube 172, and coating 176. Catheter 170 further includes tip 178, 
ports 180 and 182, and electrodes 184 and 186. Catheter 170 is able to 
accommodate incidental curvatures once it is inside a body cavity. 
Thus, a medical device having a catheter which includes flexible and 
malleable tubes has been presented with respect to specific embodiments. 
The flexible and malleable tubes provide the capability of conforming the 
catheter to the inside curves of a body cavity. Other variations of the 
present invention are obvious to one knowledgeable in the art. For 
example, the order of connecting the flexible tube and the malleable tube 
could be reversed based on the requirement of the medical device. 
Therefore, the present invention is not to be limited except by the 
appended claims.