Instrument and method for intraluminally relieving stenosis

• US 5,207,672 A
• Filed: 01/14/1991
• Issued: 05/04/1993
• Est. Priority Date: 05/03/1989
• Status: Expired due to Fees

• Current Assignee: Enterprise Medical Technology
• Original Assignee: Intra-Sonix, Inc.
• Inventors: Martinelli, Michael A., Roth, Robert A.
• Primary Examiner(s): Shay, David M.
• Application Number:
  US07/641,457
• Time in Patent Office: 841 Days
• Field of Search: 328/395, 328/392, 328/398, 328/660.1, 328/660.3, 328/660.5, 606/2-7, 606/10-19, 604/20
• US Class Current: 606/10
• CPC Class Codes: A61B 18/24 with a catheter A61B18/26, A61B18/28 take precedence
• CPC Class Codes: A61B 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2017/22059 transparent
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61B 2090/3784 both receiver and transmitter being in the instrument or receiver being also transmitter
• CPC Class Codes: A61M 25/104 used for angioplasty
• CPC Class Codes: A61M 29/02 Dilators made of swellable material balloon catheters for angioplasty A61M25/104

Abstract

An instrument for and method of effectively treating the prostatic urethra so as to relieve the symptoms associated with an enlarged urethra is disclosed. The tissue of at least selected portions of the prostate are compressed (preferably with a balloon inserted into the prostatic urethra so as to enhance hemostasis) and at least selected portions of the compressed tissue are directly irradiated (preferably with a laser beam transmitted from within the passageway in selected radial directions and moved along the prostatic urethra while exposing the tissue) so as to cause coagulation necrosis of selected portions of the compressed tissue so that as the tissue heals, the necrosed tissue slowly sloughs off during normal urination through the urinary tract so as to effectively remove the constricted portions of the prostatic urethra. Ultrasonic transducers are used from within the prostatic urethra to image the tissue as it is irradiated so as to monitor the procedure to insure proper exposure to the laser beam.

Claims

1. An instrument for use in effectively removing anatomical constrictions of the prostatic urethra, the instrument comprising:

a catheter casing sufficiently long so that a portion of the casing can be inserted into the prostatic urethra within the anatomical constrictions;

an inflatable balloon, substantially transparent to selected laser radiation and supported on the portion of the catheter casing so that the balloon is insertable into the prostatic urethra within said anatomical constrictions, the balloon being size so that when inflated within the prostatic urethra the balloon assumes a substantially fixed and uniform cross-sectional dimension so as to reconfigure at least a selected part of the tissue of the urethra into a smooth uniform cylindrical shape having an axial direction such that a corresponding portion of the prostate is squeezed from within the urethra and balloon excluding means for comprising the tissue and associated blood vessels of the corresponding portion of the prostate so as to decrease blood flow and promote hemostasis in the tissue, and means for providing for uniformity and increased depth of penetration of said selected laser radiation in the corresponding portion of the prostate;

a probe axially and rotatably movable within the casing and the balloon;

means, fixed relative to said probe, for transmitting a beam of said selected laser radiation in a direction transverse to said axial direction through the balloon into at least a volumetric portion of the tissue compressed by the balloon where an anatomical constriction exists;

a control unit, coupled to said catheter casing and said probe, including means for setting a rotational position of said probe so as to set the transverse direction of the beam of laser radiation relative to said balloon when compressed tissue is exposed to said beam of radiation, and means for moving the probe within and relative to the casing and balloon along the prostatic urethra so as to move said means for transmitting said beam of laser radiation relative to said balloon while transmitting said beam of said selected laser radiation through the balloon directly into at least a portion of the tissue compressed by the balloon; and

means, fixed relative to said probe and movable relative to said casing and balloon, for ultrasonically observing said volumetric portion of said tissue as the tissue is exposed to the beam of laser radiation.

2. An instrument according to claim 1, further including means for transporting liquid within said casing to said balloon for inflating said balloon and maintaining said balloon in an inflated state with said liquid.

3. An instrument according to claim 1 wherein said tissue has an elastic limit and said balloon is sized so that when inflated within said prostatic urethra, the pressure on said tissue will not exceed the elastic limit of the tissue of an averaged sized hyperplastic prostate gland.

4. An instrument according to claim 1, wherein said means for transmitting said beam of selected radiation includes fiber optic means, fixed relative to said probe, for directly transmitting said beam through said casing to said balloon, and reflector means for reflecting said beam at a transverse angle to said elongated direction of said prostatic urethra, said reflector means being positioned on said probe relative to the inflated balloon so as to reflect said beam from a location at equal distances to the wall of the selected part of the urethra reconfigured by said inflated balloon regardless of the rotational position of said probe when compressed tissue is exposed to said beam of radiation.

5. An instrument according to claim 4, wherein said means for ultrasonically observing said volumetric portions of said tissue includes transducer means positioned adjacent to and movable with said reflector means for transmitting an ultrasonic beam into said tissue and transducer means for receiving reflections of said ultrasonic beam from said tissue.

6. An instrument according to claim 5, wherein said transducer means includes a pair of transducers fixedly secured relative to said probe and said reflector means includes a reflector fixedly secured relative to said transducers.

7. An instrument according to claim 1, wherein said control unit includes means for moving said probe axially within and relative to the casing and balloon along the prostatic urethra at a controllable rate so as to move said means for transmitting said beam of laser radiation relative to said inflated balloon while transmitting said beam of said selected laser radiation through the balloon.

8. An instrument according to claim 7, wherein said means for moving said probe at said controllable rate is operated so that said beam of laser radiation transmitted directly into at least a volumetric portion of the tissue compressed by the inflated balloon is of sufficient power at a predetermined and constant spot size and of sufficient duration to cause coagulation necrosis of said irradiated tissue portion after said tissue is exposed to said beam of laser radiation so that as said tissue portion heals the treated and thus coagulated tissue is expelled through the urethra over time and the anatomical constriction of the prostatic urethra post-operatively effectively opens.

9. An instrument according to claim 8, wherein said means for ultrasonically observing said volumetric portion of said tissue includes means for observing said tissue prior to the exposure of said tissue to said beam of laser radiation so that the controllable rate can be determined.

10. A method of effectively removing one or more anatomical constrictions of a prostatic urethra and relieve the signs and symptoms associated with such constrictions, said method including the steps of:

inserting a portion of an instrument including an inflatable balloon which is transparent to selected radiation into the prostatic urethra so that the boon is positioned within at least a selected part of the prostatic urethra including at least one anatomical construction;

inflating the balloon so that at least a selected part of said prostate is compressed from within the anatomical constriction so as to (a) compress the tissue and associated blood vessels of the selected part so as to decrease the flow of blood in the tissue and promote hemostasis, and (b) provide for uniformity and increased depth of penetration of the selected laser radiation into the selected part of the prostate;

moving a beam of said selected laser radiation from within the prostatic urethra and balloon, in a direction relative to the compressed tissue, so as to irradiate one or more selected portions of the compressed tissue and associated blood vessels of the prostate at said constriction so that coagulation necrosis of selected portions of the prostate is caused by the laser irradiation, ultimately resulting in treated tissue being expelled through the urethra, which is turn results in an increase of cross-sectional dimensions of the prostatic urethra; and

ultrasonically observing the selected portions of the tissue and associated blood vessel forming said prostatic urethra in order to control the amount of irradiation of said tissue by said laser means.

11. A method according to claim 10, where said step of moving said laser beam includes the step of moving the laser beam relative to the balloon at a rate so that each selected portion of said tissue exposed to said laser radiation absorbs controlled levels of said radiation per unit volume of tissue.

12. A method according to claim 10, wherein said step of moving the laser beam includes the step of transmitting the beam along a transmission axis into each selected portion of the compressed tissue from the same uniformly spaced distance from the wall of said prostatic urethra.

13. A method according to claim 10, wherein said step of ultrasonically observing said tissue includes the step of ultrasonically observing said tissue before, during and after said irradiating step.

14. A method according to claim 10, wherein said step of ultrasonically observing said tissue from within said urethra includes the step of moving said beam of radiation substantially coincident with and relatively fixed with respect to said direction of ultrasonic observation during said irradiating step.

15. A method according to claim 10, further including the step of ultrasonically observing the selected portions of the tissue and associated blood vessels forming the prostatic urethra in order to allow for quantification and characterization of said tissue and determine the distance of the beam of radiation from the observed tissue.

16. A method according to claim 10, further including the step of setting the direction of the laser beam at a predetermined angle to a longitudinal direction of the prostatic urethra at which the laser beam is moved along the prostatic urethra relative to the balloon when irradiating a selected portion of the compressed tissue.

17. A method according to claim 16, further including the steps of setting the angle of the direction of the laser beam about the longitudinal direction of the prostatic urethra at each of a plurality of predetermined angles and moving the laser beam from within the prostatic urethra relative to the balloon and the compressed tissue at each of the predetermined angles.