WO1998030160A1

WO1998030160A1 - Rf intraluminal ablation device

Info

Publication number: WO1998030160A1
Application number: PCT/US1997/018689
Authority: WO
Inventors: Ingemar H. Lundquist
Original assignee: Lundquist Ingemar H
Priority date: 1996-10-21
Filing date: 1997-10-20
Publication date: 1998-07-16
Also published as: AU4905297A; TW349008B

Abstract

This invention features an intraluminal ablation device, having an elongated shaft, a handle or adapter on the proximal end of the shaft and a cartridge assembly with an elongated energy transmitting member slidably disposed within and with an insulating jacket on its exterior. The distal end of the intraluminal device and insulating jacket are configured to penetrate tissue, such as prostatic tissue, which is to be ablated. One embodiment of the intraluminal device of the invention has a mechanism to fix the relative positions of the energy transmitting member and the insulating jacket surrounding the energy transmitting member to adjust the length of the distal extremity of the energy transmitting member which extends beyond the distal end of the insulating jacket. In another embodiment the cartridge assembly is provided with a mechanism to be advanced beyond its operating position and then be retracted to its operating position to minimize tenting at the penetration site. in yet another embodiment means are provided to prevent delivery of ablation energy unless the electrodes are in their position for the procedure.

Description

RF INTRALUMINAL ABLATION DEVICE

BACKGROUND OF THE INVENTION

This invention relates to tissue ablation devices and the method of using such

devices and particularly to the treatment of benign prostatic hyperplasia (BPH).

BPH, the nonmalignant enlargement of the prostate gland, is quite common in

men as they grow older and frequently causes the constriction of the patient's

urethral canal, interfering with the flow of urine therethrough. Treatment modalities

for the BPH condition has varied over the years. For many years constricted

urethral passagewaya caused by BPH were dilated by passing a series of bogies

with increasingly larger distal tips through the constricted passageway. More

recently, a similar method has been proposed whereby a dilatation balloon on the

distal end of a catheter is expanded within the stenotic region of the urethral canal to

expand the passageway. This expansion of the stenotic urethral canal can be

effective, but the benefits are frequently short-lived, in that the constriction returns a

short while, e.g. a year or two, after the initial dilatation.

One of the more frequently used modalities is a surgical transurethral

resection of the prostate (TURP) which involves insertion of a resectoscope through

the urethra and removing the constricting tissue by means of a hot wire. However,

this procedures can result in incontinence, impotence and a variety of other

problems. Moreover, this procedure usually require general anaesthesia and a

significant hospital stay, all of which result in significant costs.

Another treatment modality of more recent origin involves debulking the

prostate gland by laser, RF, microwave energy, ultrasonic vibrations and the like which is delivered into the gland by means of an elongated energy transmitting

member inserted into the prostatic tissue to be ablated. For example, PCT

application WO 92/10142 (Makower) describes the utilization of a catheter which is

advanced into the patient's urethral canal until its distal end is situated within the

prostatic urethra and an elongated needle is curved out of the distal end of the

catheter into an adjacent lobe of the patient's prostate gland. An optical fiber is

advanced through the inner lumen of the needle into the prostate gland and laser

energy is emitted from the distal end of the optical fiber to ablate prostatic tissue. A

pair of elongated needles can be used, one needle which is curved into one lobe of

the prostate gland and the other needle curved into the opposite lobe.

Similar treatments and ablation devices for such treatments can be found in

U.S. Patent No. 4,565, 200 (Cosman), U.S. Patent No. 5.385,544 (Edwards et al),

U.S. Patent No. 5,409,453 (Lundquist), U.S. Patent No. 5,435,805 (Edwards et al),

and U.S. Patent No. 5,470,309 (Edwards et al.) where the elongated energy

transmitting member is a metallic member with an exposed portion on the distal tip

thereof which acts as an emitting electrode. High frequency electrical energy is

passed through the energy transmitting member and emitted from the exposed

portion of the energy transmitting member, which acts as an emitting electrode, to

ablate the surrounding prostatic tissue and thereby debulk the patient's prostate

gland. See also U.S. Patent No. 4,950,267 (Ishihara et al.) which discloses a laser

based device for similar functions. The above patents are hereby incorporated by

reference in their entireties. While there has been much development work in this field, the TUR technique

despite its shortcomings remains the conventional practice. What has been needed

is a system which does not require general anesthesia and which would facilitate

debulking BPH treatments which do not require extended hospital stays. The

present invention satisfies these and other needs.

SUMMARY OF THE INVENTION This invention is directed to an elongated tissue ablation device which has an

elongated shaft with an inner lumen extending therein and a handle on the proximal

end of the shaft with an interior chamber. An energy transmitting cartridge assembly

comprising an elongated energy transmitting member which has an insulating jacket

disposed about the member for a substantial length thereof and which is configured

along with its jacket to be slidably disposed within the inner lumen of the elongated

shaft of the ablation device and a cartridge housing secured to the proximal ends of

the energy transmitting member and the jacket thereof which is configured to be

slidably disposed within the inner chamber of the handle of the ablation device and

over the energy transmitting member. The energy transmitting cartridge housing is

provided with means to fix the relative longitudinal displacement between the energy

transmitting member and the insulating jacket so as to set the length of the distal

extremity of the energy transmitting member which extends out of the insulating

jacket, preferably before the energy transmitting member is advanced into adjacent

tissue for ablation. By being able to adjust the length of the energy transmitting

member which extends out of the insulating jacket, the same energy transmitting

member, and thus cartridge assembly can be used for a variety of prostate sizes. There is no need for separate cartridge assemblies for different sized prostate

glands. Moreover, the cartridge assembly is replaceable to allow for the subsequent

reuse of the shaft and handle of the ablation device.

Preferably, the cartridge housing is provided with a projection configured to

extend through a slot or opening in a wall of the handle to allow for the manual

longitudinal movement of the cartridge assembly by this projection within the

ablation device to extend the distal end of the energy transmitting member out the

distal end of the elongated sheath and into adjacent tissue such as the patient's

prostatic urethral wall and prostate gland.

In accordance with one embodiment of the invention, means are provided to

advance the energy transmitting cartridge housing within the interior chamber of the

ablation device handle beyond the operating position thereof so that the energy

transmitting member attached thereto is advanced further into a mass of tissue to be

ablated than contemplated for the ablation procedure and then withdrawn back to its

operating position. This withdrawal pulls the energy transmitting member and its

insulating jacket to minimize the tenting of the tissue through which the energy

transmitting member initially penetrates, e.g. the prostatic urethral wall. Once in

place, suitable energy, such as high frequency (RF) electrical energy, laser energy,

ultrasonic energy and the like, is passed through the elongated energy transmitting

member and is emitted from the exposed distal extremity thereof to ablate the tissue

surrounding the distal extremity.

Because the energy transmitting assembly is a completely separate unit, it

may be withdrawn after use and discarded while the shaft and handle of the ablation device may be cleaned up, sterilized and used again. Another advantageous

feature of the invention is the capability of adjusting the length of the energy

transmitting member either before inserting the ablation device into the patient or

after the device is inserted to handle a variety of prostate sizes. These and other

advantages will become more apparent from the following detailed description of the

invention when taken in conjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an elevational view of an elongated ablation device which embodies

features of the invention.

Fig. 2 is an enlarged elevational view of the distal extremity of the ablation

device shown in Fig. 1.

Fig. 3 is an end view of the distal extremity shown in Fig. 2.

Fig. 4 is a transverse cross-sectional view of the distal extremity of the

ablation device shown in Fig. 2 taken along the lines 4-4.

Fig. 5 is a longitudinal cross-sectional view of the ablation device shown in

Fig. 1.

Fig. 6 is a longitudinal cross-sectional view of the ablation device shown in

Fig. 5 taken along the lines 6-6.

Fig. 7 is a transverse cross-sectional view of the ablation device shown in Fig.

6 taken along the lines 7-7.

Fig. 8 is an exploded perspective view of the handle of the ablation device

shown in Fig. 1. Fig. 9 is a plan view, partially in section, of the cartridge assembly shown in

Fig. 8.

Fig. 10 is a longitudinal cross-sectional view of the cartridge assembly shown

in Fig. 9 taken along the lines 10-10.

Fig. 11 is an exploded perspective view of the cartridge assembly shown in

Figs. 9 and 10.

Fig. 12 is a partial elevational view, partially in section, of an alternative

embodiment which includes means to ensure energy delivery of electrical energy

only in a single operable location.

Fig. 13 is a rear view, partially in section, of the embodiment shown in Fig. 12.

Fig. 14 is a top view of the PC board shown in Figs. 12 and 13 schematically

showing the arrangement of electrical posts and electrical conductors which facilitate

the transmission of electrical energy at the operable location.

Fig. 15 is an elevational view of another embodiment wherein the electrodes

have a looped proximal ends which engage electrical contact points on the PC

board.

Fig. 16 is a top view, partially in section, of the embodiment shown in Fig. 15.

DETAILED DESCRIPTION OF THE INVENTION Reference is made to Figs. 1-5 which illustrate an ablation device 10

embodying features of the invention which generally includes a handle or adapter 11

having an interior chamber 12, an elongated shaft 13 and a pair of conduits 14

within the elongated shaft configured to receive elongated electrodes 15 and 16

having insulating jackets 17 and 18. The electrodes 15 and 16 are part of an electrode cartridge 19 assembly which includes a cartridge housing 20. The

cartridge housing 20 receives and secures the proximal ends of the electrodes 15

and 16 and the jackets 17 and 18 and is slidably disposed within the interior

chamber 12 of the handle or adapter 11.

Each of the opposing walls 21 and 22 of the handle 11 are provided with

recesses 23 and 24 which controls the movement of the cartridge housing 20 within

the interior chamber 12. The locating pins 25 and 26 on the exterior of the cartridge

housing 20 ride along the ledges 27 and 28 defined by the recesses. Position A, as

shown in Figs. 5 and 11 , is the maximum thrust position for the cartridge housing,

position B is the operating position and position C is a nonoperating at-rest position.

While not shown in the drawings, a biasing means (e.g. a helical spring) may be

provided within the distal end of the interior chamber 12 to urge the return of

cartridge housing 20 from position A to position B as shown in Fig. 5.

The distal end or nose piece 28 of the elongated shaft 13 is rounded or blunt

to minimize trauma to the patient's urethra upon advancing the elongated shaft to

the desired location adjacent to the patient's prostate gland. The distal ends of the

electrode conduits 14 within the nose section 28 are curved so as to direct the distal

ends of the electrodes 15 and 16 and the insulating jackets 17 and 18 thereof

through the adjacent urethral wall into the patient's prostate gland. As shown in

Figs. 2 and 3, the distance the electrodes 15 and 16 extend out of the jackets 17

and 18 can be adjusted to provide a desired exposed electrode area to

accommodate a wide range of prostate gland sizes. The mechanism for adjustment of the electrode exposure beyond the distal end of the insulation jacket 16 will be discussed hereinafter.

The electrode conduits 14 are defined by tubular guide members 29 which

extend to the stop member 30 within the interior chamber 12 of the handle 11. The

elongated shaft 13 of the ablation device 10 also has a central passageway 31

defined by tubular member 32 for an optical fiber 33 which has an angled face 34 for

lateral viewing of the stenotic region of the prostatic urethra to facilitate the desired

positioning of the electrodes within the patient's prostate gland. An eyepiece 35,

including lens elements (not shown), optically connected to the optical fiber 31 , is

provided on handle 11 to allow the physician or other operator to view the treatment

site. The elongated shaft 12 is also provided with a channel 36 defined by tubular

member 37 which allows for the delivery and aspiration of suitable fluids such a

saline to and from the treatment site.

The cartridge housing 20 is provided with projection or tab 38 on its upper

wall portion which extends out the slot 39 in the upper wall 40 of the handle 11 to

allow for the manual movement of the cartridge housing within the interior chamber

12 and, as a result, the longitudinal movement of the electrodes 15 and 16 and the

jackets 17 and 18 within the electrode conduits 14.

The relative longitudinal positions between the electrodes 15 and 16 and the

insulating jackets 17 and 18 may be adjusted by moving the tabs 41 and 42 which

extend out of the slots or openings 43 and 44 in the upper wall of the cartridge

housing 20. The electrodes 15 and 16 are secured by their proximal ends within the

legs 45 and 46 of slider member 47 as shown in Figs. 10 and 11 by a metallic collars 48 (only one shown in the drawings) which also facilitates electrical contact with the

PC board 49 secured with the interior of the slider member 47. The proximal ends of

the insulating jackets 17 and 18 are secured within the distal end of the slider

member 47 by means of a bearing or sealing collars 50 and 51 each of which has a

central passageway for the electrode 15 and 16 as shown in Fig. 10. Each of the

slots or openings 43 and 44 are provided with a plurality of recesses 52 and 53

which are configured to receive the protrusions 54 and 55 at the base of the tabs 41

and 42. The most distal recess provides the maximum electrode exposure, whereas

the most proximal recess provides the least exposure.

Also shown in Figs. 9 and 10 are electrical conductors 56 and 57 which

extend out the distal ends of the insulating jackets 17 and 18. These conductors are

connected by their distal ends to thermocouples (not shown) disposed in the distal

ends of the jackets, and are electrically connected by their proximal ends to the PC

board 49. The proximal extremity of the PC board 49 extends out proximal end of

the cartridge housing 20 and is suitably connected to a signal processor for

temperature sensing and to a high frequency power source by conventional means

not shown.

The dimensions of the ablation device 10 are selected to fit the particular

procedure which the device is to perform and the patient on which the procedure is

to be performed. The handle 11 is sized and preferably shaped to comfortably fit

within the hand of the operator. The handle, cartridge housing and other

components may be formed of suitable polymer materials such as polyethylene,

polypropylene, polyvinyl chloride, polycarbonate and the like. The spring 60, shown in Fig. 8 and further described below with respect to ensuring electrode actuation

only at the proper location of the electrodes is operation, which urges the cartridge

housing 20 upwardly toward the top of the inner chamber 12 of the handle 11 is

preferably made from metallic materials such as stainless steel and the like. Other

conventional materials may also be utilized.

Reference is made to Figs. 12-14 which describe a system for ensuring that

the laser can be fired only when the electrodes are at a desirable location. As

shown, the springs 60 and 61 , which urge the cartridge housing 20 toward the upper

wall 40 to contact electrical contact posts 62 and 63 and 64 and 65 which protrude

slightly from the lower surface of the PC board 49. The RF electrical power, as

shown in Fig. 13, is delivered through electrical conductor 66 and 67 to posts 62 and

64 and the power is delivered from posts 63 and 65 to electrical conductors 68 and

69 to the electrodes 15 and 16 respectively. As shown in Fig. 14, RF power is

deliverable to the electrodes 15 and 16 only when the springs 60 and 61 electrically

interconnect the electrical posts 62 and 63 and 64 and 65. This ensures that the RF

energy burst will be delivered to the electrodes only when the electrodes are in the

correct position.

In Figs. 15 and 16 an embodiment is shown which ensures the positioning of

the electrodes 15 and 16 within the assembly so that the distal extremity of the

electrodes can be preshaped and the orientation of the preshaped distal extremity of

the electrodes can be controlled. The proximal ends of the electrodes 15 and 16 are

formed into loops 70 and 71 so that the lower portion of each of the loops contact

the electrical contacts 72 and 73 on the PC board. The upper portion of the loops presses against the upper portion of the cartridge housing 20 to ensure pressured

contact with the electrical contacts on the PC board. The electrodes are provided

with positioning collars 74 and 75 crimped thereon which are configured to fit into the

series of recesses 76 and 77 provided to control the length of the distal portion of

the electrodes 17 and 18 which extend into the patient's prostate. In this

embodiment shown, the electrodes are fixed within the insulation and several

electrodes are usually provided with different lengths of exposed electrodes for

various sized prostates.

While the invention has been described herein primarily in terms of certain

preferred embodiments, various modifications and improvement can be made to the

invention. For example, the electrode may be replaced with an optical fiber system

which is optically connected to a source of laser energy. Other changes include

replacing the electrode with an elongated metallic style which is suitable for

transmitting ultrasonic vibrations. A variety of other modifications may be made

without departing from the scope of the invention. Moreover, although individual

features of one embodiment of the invention may be discussed herein or shown in

the drawings of the one embodiment and not in other embodiments, it should be

apparent that individual features of one embodiment may be combined with features

another embodiment or some or all of the embodiments.

Claims

WHAT IS CLAIMED IS:

1. An elongated intraluminal device for ablating tissue, comprising

a) an elongated shaft having proximal and distal ends, at least one

inner lumen which extends from the proximal end to the distal end of the shaft

and means on the distal end of the shaft for directing energy delivering means

laterally;

b) a handle on the proximal end of the shaft having an interior

chamber, a wall portion which defines at least in part the interior chamber;

c) an elongated cartridge assembly comprising

an elongated energy transmitting member which is at least in

part configured to be slidably received within the inner lumen extending

within the shaft of the ablation device and to extend out the distal end

of the ablation device, and which has proximal and distal extremities,

means to connect the proximal extremity of the energy transmitting

member to a source of suitable energy, means to emit energy from the

distal extremity toward tissue to be ablated and an insulating jacket

disposed about a substantial length of the energy transmitting member,

a cartridge housing connected to the proximal end of the

energy transmitting member which is configured to be slidably

disposed within the interior chamber of the handle of the

ablation device and which has means to fix the length of the

distal end of the energy transmitting member extending out of

the distal end of the insulating jacket before the cartridge assembly is longitudinally moved so as to insert the distal end of

the energy transmitting member into desired tissue; and

d) means to move the cartridge assembly longitudinally within the

ablation device.

2. The ablation device of claim 1 including means to fix the cartridge

housing at an operating position within the interior chamber of the handle.

3. The ablation device of claim 2 including means to allow the cartridge to

be advanced distally beyond the operating position so as to extend the distal end of

the energy transmitting member beyond desired location and to be returned to the

operating position to withdraw the energy transmitting member to locate the distal

end of the energy transmitting member at its operating position within the tissue,

thereby reducing the tenting of the tissue through which the said distal end initially

penetrates.

4. The ablation device of claim 1 wherein a longitudinally oriented slot is

provided in a wall portion of the handle which is in fluid communication with the

interior chamber and a projection in provided on the cartridge housing which extends

out the slot to facilitate the manual longitudinal translocation of the cartridge housing

within the inner chamber of the handle.

5. The ablation device of claim 3 wherein the interior of the handle is

provided with opposed recesses within side walls of the handle which aid in guiding

the cartridge housing within the interior chamber.

6. The ablation device of claim 5 wherein the cartridge is provided with

guiding pins extending from the exterior sides thereof which are configured to ride

within the recesses provided within the side walls of the handle to guide the cartridge

housing to an operating position within the handle and another position distal to the

operating position.

7. An elongated intraluminal device for ablating tissue, comprising

a) an elongated shaft having proximal and distal ends, at least one

inner lumen which extends from the proximal end to the distal end of the

shaft;

b) a handle on the proximal end of the shaft having an interior

chamber, a wall portion which defines at least in part the interior chamber;

c) an elongated cartridge assembly comprising

an elongated energy transmitting member which is at least in

part configured to be slidably received within the inner lumen extending

within the shaft of the ablation device and to extend out the distal end

of the ablation device, and which has proximal and distal extremities,

means to connect the proximal extremity of the energy transmitting

member to a source of suitable energy, means to emit energy from the

distal extremity toward tissue to be ablated and an insulating jacket

disposed about a substantial length of the energy transmitting member,

a cartridge housing connected to the proximal end of the energy

transmitting member which is configured to be slidably disposed within

the interior chamber of the handle of the ablation device and which has means to allow the cartridge to be longitudinally advanced within the

interior chamber of the handle to an operating position and to be

advanced distally beyond the operating position so as to extend the

distal end of the energy transmitting member secured to the cartridge

housing beyond desired location and to be returned to the operating

position to withdraw the energy transmitting member to locate the

distal end of the energy transmitting member at its operating position

within the tissue, thereby reducing the tenting of the tissue through

which the said distal end initially penetrates.

d) means on the distal end of the shaft for directing laterally the

distal extremity of the energy transmitting member; and

e) means to move the cartridge assembly longitudinally within the

ablation device.

8. The ablation device of claim 7 wherein the cartridge housing includes

means to fix the length of the distal end of the energy transmitting member which

extends out of the distal end of the insulating jacket before the cartridge assembly is

longitudinally moved within the interior chamber of the handle so as to insert the

distal end of the energy transmitting member into desired tissue adjacent the distal

end of the elongated shaft of the ablation device.