INSTRUMENT AND METHOD FOR INTRALUMINALLY RELIEVING STENOSIS

Abstract: An instrument for and method of effectively dilating a stenotic region of a passageway of a portion of the living body, preferably the prostatic urethra, so as to relieve the symptoms associated with the stenosis. In the preferred system the tissue of at least selected portions of the prostate (172) are compressed (preferably with a balloon (8) inserted into the prostatic urethra so as to enhance hemostasis), and at least selected portions of the compressed tissue are denatured (preferably with a laser beam transmitted from within the passageway in selected radial directions) so that as the denatured tissue heals, the denatured tissue tends to shrink so as to effectively dilate the portions of the prostatic urethra. Ultrasonic transducers are used from within the prostatic urethra to image the tissue as it is denatured so as to monitor the procedure to insure proper exposure to the laser beam.

Description: INSTRUMENT AND METHOD FOR INTRALUMINALLY RELIEVING STENOSIS -1- The present invention relates generally to intraluminal surgery, and more particularly to an improved instrument for and technigue of trans- luminally opening any constricted regions of a 5 passageway through a portion of a living body, and in particular, the prostatic urethra of an enlarged prostate. As is generally well known the prostate is located at the base of the bladder, where it surrounds a 10 portion of the urethra, the tube connecting the bladder to the outside world. The function of the prostate is to produce a fluid which becomes a part of the ejaculated semen (which is also carried through the urethra) . As men grow older, the tissue of the 15 prostate often begins to enlarge, a condition called hyperplasia. As the bulk of the prostate enlarges, the gland begins to constrict the portion of the urethra passing through the prostate and thus prevent the normal flow of urine, a condition known as benign 0 prostatic hypertrophy or hyperplasia (BPH) . As BPH develops, one or more constricted or stenotic regions within the prostatic urethra can from time to time obstruct the flow of urine; so the signs of BPH are difficulty starting urination, dribbling following 5 urination, reduced force of the stream of urine, a tendency to urinate freguently in small amounts as well as pain and discomfort. As a result an increase in urinary tract infections can occur. The symptoms are common; 75% - 80% of men over the age of fifty are 0 affected. See, for example, the Harvard Medical Health Letter? September 1988; Volume 13; Number 11; pages 1 - 4 and Castaneda, Flavio et al.; "Prostatic Urethra: Experimental Dilation in Dogs"; Radiology; June, 1987; pp. 645 - 648. In fact recent statistics apparently reveal that a 50 year old man has a 20 - 25% chance of undergoing a prostatectomy during his lifetime. See Castaneda et al., supra. It is currently estimated that about 500,000 prostatectomies are performed each year in the United States alone. See Castaneda, Flavio et al.; "Benign Prostatic Hypertrophy: Retrograde Transurethral Dilation of the Prostatic Urethra in Humans" Radiology; June, 1987, pp. 649-653. When the obstructive symptoms of BPH become bothersome, the constricted portions of the urethra are usually reopened surgically. Current accepted treatment for BPH involves either open or transurethral surgery, which is costly and is associated with an acceptable but undesirable degree of mortality (estimated from 1.3% to 3.2% - see Castaneda, Flavio et al.; "Benign Prostatic Hypertrophy: Retrograde Transurethral Dilation of the Prostatic Urethra in Humans" Radiology; June, 1987, pp. 649-653) and with a significant degree of morbidity, especially in less fit patients. One popular surgical procedure for BPH, as an alternative to open surgery, is a transurethral resection of the prostate, or TURP. The transurethral resection involves inserting a resectoscope through the urethra. A spring wire, adapted to carry an electric current, is inserted through the resectoscope for use in removing tissue. The wire carries one current for cutting away "chips" of tissue with the resectoscope and another current for cauterizing the remaining tissue to minimize bleeding. Typically, as much as two cubic inches of tissue are removed in this way. An alternative but similar procedure is the radial prostatoto y. In this procedure radial cuts, parallel to the longitudinal direction of the prostatic urethra, are made transurethrally into the prostate with the wire of a resectoscope by removing tissue along longitudinal incision lines at preselected angles to one another about the longitudinal direction of the prostatic urethra (such a procedure has been suggested for removing constrictions of a stenotic region of upper air passageways by vaporizing tissue with a laser beam to form radial cuts in the stenotic region of the air passageways—see Shapshay et al. ; "Endoscopic Treatment of Subglottic and Tracheal Stenosis by Radial Laser Incision and Dilation"; Annals of Otology. Rhinology & Laryngology; Vol. 96, No. 6, November-December 1987, pp. 661-664) . The TURP and radial prostatotomy surgical technigues are not trivial nor inexpensive, though the actual procedures can ordinarily be done quickly. The procedure carries similar risks as many of those associated with other general surgical procedures, including those associated with the use of general anesthesia. Other surgical hazards include stricture formation at the urethra or bladder neck, post-manipulation pain or bladder spasm, urinary tract infections, and reactive urethral swelling which can cause urinary obstruction and epididymitis. Other complications include infection and retrograde ejaculation. Further, the post-operative care following a TURP procedure requires a prolonged hospital stay, creating substantial costs for medical care. The appropriate DRG (Diagnostically Related Group) , currently designated by Medicare, for the TURP procedure presently entails an average length of hospital stay of 6.9 days. For a discussion of current pressures to reduce allowable Medicare fees for the TURP procedure and the impact of such reduced fees on urological patient care and the American urologist, see Holtgrewe, H.L. et al.; "Transurethral Prostatectomy: Practice Aspects of the Dominant Operation in American Urology"; The Journal of Urology; volume 141 (1989); pp. 248-253. In addition, some men have reported sexual dysfunction following the resection. Certain men have also become incontinent as a result of the surgery because of inadvertent damage done to the external sphincter muscles positioned at the apex of the prostate for controlling urine flow. The surgery usually results in moderate discomfort with some post-operative bleeding being usual. As a result of the trauma that many men experience from TURP and the relatively long in-patient care required for post operative recovery, alternative techniques of treating BPH are being investigated. For example, using hormonal treatments to prevent or reverse prostate enlargement has long been considered in the treatment of prostate enlargement. Male hormones are known to promote growth of the gland. However, there have been some uncertainties about the role played by hormones in creating BPH. Other devices for treatment of the prostate utilize heat, as for example a device sold by Armonite, Inc. of New York. The latter device provides thermal therapy to the prostate transrectally by radiating the prostate with microwave heat which is claimed to result in the shrinkage of the affected prostate tissue. The long term results of such therapy are currently inconclusive. Methods of injecting medications directly into the prostate through a catheter extending into the prostatic urethra have been attempted. However, these injections are frequently ineffective due both to the poor absorption of such medications by the prostate, as well as to the difficulty inherent in positioning and retaining the catheter with respect to the affected area, and generally result in reoccurring prostatic disorders. An example of a device for positioning such a catheter and injecting medications into the prostate is shown in U.S. Patent 3,977,408 issued to MacKew. Another approach to treating BPH is a technique known as transurethral balloon dilation of the prostate. In this approach a catheter having an inflatable balloon positioned on the distal end of the catheter is transurethrally inserted into the portion of the urethra extending through the prostate. The balloon is then inflated so that the expanding balloon dilates the urethra and is held in its inflated state for a limited period of time, e.g., between ten and sixty minutes. See, for example, Castaneda, et al.; "Prostatic Urethra: Experimental Dilation in Dogs"; Radiology; June, 1987, pp. 645-648; and Castaneda, et al.; "Benign Prostatic Hypertrophy: Retrograde Transurethral Dilation of the Prostatic Urethra in Humans" Radiology; June, 1987, pp. 649-653. See also U.S. Patent No. 4,660,560 issued to Lester Klein. The balloon described in the last mentioned Castaneda et al. article is inflated at a pressure of between 3 and 6 atmospheres and held under pressure for about ten minutes. During the balloon dilation procedure the tissue of the urethra must be expanded just beyond its normal elastic limit otherwise the urethra will not remain dilated for very long. Accordingly, the balloon is sized to expand, for example, to a 25mm diameter so as to cause the tissue within the averaged sized urethra to stretch to the point of actually tearing or cracking so that when the tissue heals, permanent fissures will remain in the urethra so that the latter will remain dilated. But even expanding the tissue just beyond the elastic limits does not necessarily insure long term effects on relieving the stenosis and constriction of the urethral walls due to the nature of the resilient muscle tissues and large bulk of the hypertrophied prostate which has a tendency to rebound after temporary compression. See U.S. Patent No. 4,762,128 issued to Rosenbluth. Accordingly, the latter patentee proposes to insert a stent in the prostatic urethra after being dilated by the balloon and removing the stent at a later time. The use of laser radiation has been described for removing tissue of the prostate gland so as to remove tumors or all or part of the gland as an alternative to the electrocautery resection technique described above. See U.S. Patent No. 4,672,963 issued to Dr. Israel Barken and Smith, Jr., Joseph A. et al.; "Laser Photoradiation in Urologic Surgery"; The Journal of Urology; Vol. 31, April, 1984, pp. 631-635, cited therein. However, use of a laser to remove tissue from the prostate would not necessarily reduce post-operative bleeding and trauma, impotence and incontinence. The device described in U.S. Patent No. 4,672,963 uses a computer to continuously adjust the amount of laser radiation transmitted to the prostate during the procedure. Accordingly, the device includes an ultrasonic probe, inserted transrectally or positioned externally, for imaging the prostate in real time during the procedure so as to provide real time data regarding the destruction of the prostate tissue so as to enable the computer to adjust the laser radiation accordingly. Transrectal and external ultrasonic imaging of the prostate are well known as further suggested by Sanders, R.C. et al., "Update on Prostatic Ultrasound", Urologic Radiology 1987; Fleischer, Arthur C. , "Prostatic Endosonography - A Potential Screening Test"; Diagnostic Imaging. April 1987, pp. 78-82; and Lee, Fred, "Prostatic Evaluation by Transrectal Sonography: Criteria for Diagnosis of Early Carcinoma", Radiology. Vol. 158, pp 91-95, January, 1986. -8- It is a general object of the present invention to provide an improved instrument for and technique of relieving the constrictive conditions of a constricted passageway of a body part in a manner that reduces or substantially eliminates the above-noted problems. Another object of the present invention is to provide an improved instrument for and technique of relieving the symptoms of BPH while substantially reducing the length and degree of post-operative care. And another object of the present invention is to provide an improved instrument for and technique of relieving the symptoms of BPH while reducing or substantially eliminating post-operative bleeding and trauma, impotence and incontinence associated with current TURP and other resection procedures. Yet another object of the present invention is to provide an improved instrument and technique of relieving the symptoms of prostate enlargement without the need of hormonal treatments or long term heat therapy. Still another object of the present invention is to provide an improved instrument for and technique of denaturing selective portions of the prostate so as to cause subsequent shrinkage of those portions of the prostate and effectively increase, post operatively, the internal diameter of the prostatic urethra. And yet another object of the present invention is to provide an improved instrument for and technique of compressing at least selected portions of a prostate preferably within the elastic limit of the tissue so as to improve hemostasis and so that selected tissue of the compressed portions can be subsequently denatured so as to cause shrinkage of those portions of the prostate so treated and effectively increase the post operative internal cross-sectional diameter of the prostatic urethra. And still another object of the present invention is to provide an improved instrument and technique which allows the user to view, intraluminally, selective tissue, in real time during an operative procedure for dilating the passageway so as to insure selective denaturing of portions of the lumen tissue. And yet another object of the present invention is to achieve the foregoing objects with a surgical technique and instrument for generally treating, intraluminally, any stenotic regions within the lumen of a living body so as to post-operatively effectively open such regions. These and other objects of the present invention are achieved by an instrument for and method of effectively dilating a passageway through a portion of a body part so as to relieve the symptoms from constrictions within the passageway. In accordance with the present invention, selected portions of the tissue of the body are denatured. Such denatured tissue tends to shrink as it heals so as to post operatively effectively dilate the passageway. As used herein, the term "denature" means the modification of the molecular structure of the tissue (as a protein or DNA) , preferably by heating the tissue with a beam of laser radiation having a wavelength at which some of the radiation is aborbed by the tissue (although it is possible that such modification can occur in other ways) , so as to destroy or diminish some of the original properties and especially the biological activity. In this context the denaturing process is capable of producing a general coagulation necrosis of the treated tissue without actual excision or vaporization of the tissue so as to distinguish the process from those describe, for example, in European Patent Application 85402067.4 of Dr. Richard J. Spears, published May 28, 1986 under Publication number 0182689 (in which the heat required to fuse arterial plaque, compressed with an inflated balloon so that blood is trapped within the fissures of the plaque, is less than that which would produce general coagulation necrosis for the obvious reason that the biological activity of the tissue needs to be preserved) or in the Shapshay et al. article, supra (where the tissue is excised by vaporization) . Preferably, the tissue of at least selected portions of the body part are compressed (preferably with a balloon inserted into the passageway) so as to improve hemostasis, and at least selected portions of the compressed tissue are denatured (preferably with a laser beam transmitted from within the passageway in selected radial directions) so that as the denatured tissue heals, the treated tissue region contracts so as to effectively dilate the natural passageway. When the tissue is denatured with a laser beam the step of compressing the tissue prior to denaturing has the additional benefit of allowing for more uniform absorption of the laser energy by the affected tissue. -11- Ultrasonic transducers are preferably used from within the passageway to image the tissue as it is denatured so as to monitor the procedure to insure proper exposure to the laser beam, the intensity and direction of which is controlled by the surgeon. Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the apparatus possessing the construction, combination of elements, and arrangement of parts exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims. For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein: Fig. 1 is a cross-sectional side view of the control unit of the preferred embodiment of the present invention; Fig. 2 is an enlarged cross-sectional side view of a portion of the control unit shown in Fig. 1; Fig. 3 is an enlarged cross-sectional side view of another portion of the control unit shown in Fig. 1; Fig. 4 is a cross-sectional side view of the remote end portion of the transducer and laser probe forming a part of the preferred catheter unit of the present invention; Fig. 5 is a cross-sectional side view of the remote end portion of the catheter casing of the preferred catheter unit of the present invention provided with a stylet so that the casing can be inserted into the prostatic urethra; Fig. 6 is the same cross-sectional side view of the remote end portion of the catheter with the balloon inflated and the transducer and laser probe positioned in place with the casing of the catheter unit. Fig. 7 is a block diagram of the system connected for use; Fig. 8 is an anatomical illustration of the catheter casing and stylet positioned in place so that the balloon is disposed within the prostatic urethra; Fig. 9 is an isolated anatomical illustration showing the insertion of the catheter casing and stylet into the prostatic urethra; Fig. 10 is an anatomical illustration showing the catheter unit in place and selected tissue exposed to laser radiation so as to denature the tissue; and Figs. 11A-11C are anatomical cross-sectional views through a prostate generally normal to the elongated direction of the prostatic urethra for illustrating the effective dilation of the prostatic urethra as a result of the procedures described herein. Generally, in accordance with the method of the present invention a unique surgical procedure is provided which is generally useful in effectively dilating a stenotic region in a passageway through a part of a living body, and in particular, useful in relieving the symptoms of BPH. The procedure is preferably carried out using the instrument of the present invention. Generally, the instrument preferably includes means for transluminally delivering laser radiation at a power level and for a duration so as to denature selected portions of the living body (i.e., heated sufficiently to denature the protein of the affected tissue) so that as the denatured tissue heals the tissue shrinks so as to effectively open the previously constricted passageway. The instrument preferably includes means for compressing the targeted tissue so as to enhance hemostasis and allow for uniform absorption of laser energy. The preferred system and method described herein is particularly adapted for relieving the symptoms of BPH by effectively dilating any stenotic regions of the prostate. It is believed that sufficient compression can be placed on the prostate gland, from within the prostatic urethra out, so as to achieve the desired results without exceeding the elastic limit of the tissue. The preferred instrument further includes means for transurethrally ultrasonically viewing at least a portion of the prostate tissue so that the portions of the prostate to be irradiated can be selected by the user, and the selected tissue exposed to the laser radiation can be observed and monitored by the user in real time during the denaturing part of the procedure. This observation is particularly facilitated by the fact that denatured tissue becomes strongly echogenic, i.e., visible by ultrasound imaging. Referring to Figs. 1-6 the instrument of the present invention generally comprises a control unit 4 (whose detail is shown in Figs. 1-3) , and catheter unit 6 (whose detail is shown in Figs. 4-6) . The catheter unit 6 is adapted to cooperate with the control unit 4 so that the user can carry out the procedure. As described in greater detail hereinafter, the catheter unit generally includes an inflatable balloon 8, disposed at the remote end of the catheter unit, for temporarily dilating at least a portion of the prostatic urethra and sized so as to compress the tissue of an averaged sized prostate gland enlarged by BPH. The catheter unit also includes means for transmitting a laser beam along an axis transverse to the general direction of the urethra so that the laser beam can be selectively directed into portions of the tissue compressed by the balloon 8. The amount of laser radiation is sufficient to denature the exposed tissue along the direction of the laser beam axis. As the tissue heals, the tissue will contract so as to effectively increase the post-operative internal cross-sectional diameter of the prostatic urethra and thus increase urinary flow. Finally, as illustrated in Fig. 4, the catheter unit 6 preferably includes an ultrasound transmitter and receiver, 10 and 12, mounted on a shaft 14 and extending through and sealed within sleeve 16, which in turn, as best shown in Fig. 6, is positioned and axially movable within an outer casing 18 which forms the outer sleeve of the catheter unit. The ultrasound transmitter 10 and receiver 12 provide real time imaging while the catheter unit is in place within the prostatic urethra, so that the specific areas to be exposed to laser radiation can be easily selected and monitored while exposed to the laser radiation. The foregoing will be described in greater detail hereinafter. More specifically, the control unit 4 is shown in greater detail in Figs. 1-3. The control unit 4 comprises a housing 20 including a hand grip 22, although the grip may be omitted if desired. The housing includes a hollow rear cylindrical portion 24 for receiving a mounting plate 26 for supporting the scanning motor 28. The scanning motor includes means for sensing the angular position of the rotor of the motor (not shown in Figs. 1-3, but indicated in Fig. 7 as shaft encoder 168 and described hereinafter) . The rotor shaft of the motor 28 is connected through the motor coupling 30 to the drive shaft 32, which in turn is positioned in the two bearing assemblies 34 and 36, respectively supported in supports 40 and 42, so as to be rotatable about the axis of rotation 38. As shown in greater detail in Fig. 2, support 42 is preferably cylindrically-shaped and includes the radially extending portion 44 for supporting the bearing assembly 36 and the axial extending cylindrical wall portion 46 secured to the wall of the housing 20. A connector assembly 48 is secured to the end of and adapted to rotate with the shaft 32. Assembly 48 includes at least two electrical connectors 50 which are suitably wired with leads 52. The latter are threaded through a hollow portion of the shaft 32 to an electrical anchor 54, which in turn is connected to the flex cable 56, Flex cable 56, in turn, is connected to the printed circuit assembly board 58 which carries the various electronic components required to operate the units 4 and 6. As shown in Fig. 2 , a nozzle assembly 60 is suitably secured to the cylindrical wall portion 46 of the support 42 and includes a main body portion 62 and an elongated end portion 64 (best shown in Fig. 3) . An elongated hollow passageway 66 extends the entire axial length of the assembly 60 coaxial with axis 38. The passageway 66 is provided with at least four sections 68, 70, 72 and 74. The first section 68 is provided in the proximal end of the main body portion 62 of the assembly 60 and is of a relatively large diameter. The intermediate section 70 of the passageway is of an intermediate diameter, while the third section 72 is of a yet smaller diameter. The fourth section 74 of passageway 66 is provided at the opposite remote end of the elongated end portion 64 and is of a relatively small diameter. A hollow adjusting sleeve 76 is shown disposed in the second section 70 of passageway 66 and is axially adjustable along the axis 38. A set screw 78 extends through the wall of the body portion 62 and engages an axially extending groove 80 formed in the outer surface of the sleeve 76 so as to fix the sleeve in place. Sleeve 76 supports the bearing assembly 82. A hollow inner sleeve 84 is rotatably supported within the bearing assembly 82. A second connector assembly 86 is secured to the end of the inner sleeve 84 opposite the connector assembly 48 and is adapted to rotate with the sleeve about the axis 38. Assembly 86 includes a pair of electrical connectors 88 connected to and adapted to rotate with the electrical connectors 50 of the assembly 48 about the axis 38. The shaft 14 is secured within the inner sleeve 84 so as to rotate with the sleeve. As will be more evident hereafter, wires 150 extending through the shaft 14 from the ultrasound transmitter and receiver 10 and 12 are connected to the connectors 88 so as to connect the transmitter and receiver to the assembly board 58. The end of the inner sleeve 84 is mounted in an oil seal 90, secured within the third section 72 of the passageway 66 and sealing the third section from the second section 70. Fill and vent ports 92 and 94 are provided in the wall of main body portion 62 of the nozzle assembly 60 for filling and emptying oil into the third section of the passageway which fills the third and fourth portions 72 and 74 of the passageway 66 and the spaces between the shaft 14 and the sleeve 16 of the catheter unit 6, as will be more evident hereinafter. Again referring to Fig. 2, a laser fiber port 100 is provided in the main body portion 62 of the nozzle assembly 60 for receiving a laser fiber connector 102. The connector 102 is connected to laser fibers 104 applied on or extending through the "probe" formed by shaft 14 and sleeve 16 to the remote end of the probe shown best in Fig. 4 and described hereinafter. The connector 102 is adapted to be connected to a laser beam delivery system as described in greater detail hereinafter. As shown in Fig. 3, the sleeve 16 is secured at one end to the end of the elongated end portion 64 of the nozzle assembly 60 with any suitable means so as to hermetically seal the two together and allow oil inserted into the fill port 92 to flow into spaces provided between the shaft 14 and sleeve 16. A linear adjustment assembly 110 is used to connect the control unit 4 with the catheter unit 6. Assembly 110 is coaxially mounted on the elongated end portion 64 of the nozzle assembly 60. Assembly 110 includes an outer tubular housing 112 mounted on the elongated end portion 64 of the nozzle assembly 60 coaxial with the axis 38. Housing 112 is hermetically secured at its remote end at 114 to the outer casing 18 of the catheter unit 6 so that fluid can be introduced between outer casing and the sleeve 16 of the catheter unit. Accordingly, a fluid seal 116 is used to mount the sleeve 16 within the housing 112 so as to seal the remote end portion of the housing and the spaces between the outer casing 18 and sleeve 16 from the remainder of the housing 112. Further, a fluid port 118 is provided between the seal 116 and the remote end of the assembly 110 for introducing a fluid into the spaces between the casing 18 and sleeve 16. The fluid used to inflate the balloon is transparent to both the laser beam and ultrasound transitted through the fluid. The fluid will depend on the particular application of the device. For most applications an inert liquid such as water is chosen so that in the invent of rupture of the balloon the liquid will not effect the tissue to which the water -19- is exposed. A duck bill valve 120 is provided between the port 118 and the seal 116 so that the control unit 4, shaft 14 and sleeve 16 can be inserted and withdrawn from the linear adjustment assembly and the casing 18, while substantially maintaining the fluid pressure within the casing as for example when the balloon 8 is inflated. Assembly 110 also includes a rack and pinion gear assembly 122, 124, with the rack gear 122 secured to the outer surface of the elongated end portion 64 of the assembly 60 and the pinion gear 124 secured to the housing 112 so that rotation of the pinion gear 124 moves the shaft 14 and sleeve 16 (axially fixed to the nozzle assembly) relative to the outer casing 18 along the longitudinal axis of the catheter unit, defined by axis 38, for reasons which will become more evident hereinafter. Referring to Figs. 4-6, the catheter unit 6 will be described in greater detail. As shown best in Figs. 5 and 6, the balloon 8 is open at both ends. One end of the balloon is secured to the remote end 130 of the casing 18 of the unit 6 so as to form a hermetic seal between the balloon and the casing wall so that water will not leak. Similarly, the other end of the balloon is secured to the tip section 132 so as to form a hermetic seal between the balloon 8 and the tip section. A bulge 134 is provided adjacent the remote end where the balloon 8 is secured to the casing so as to provide an optional marker which can be felt transrectally by the user of the device when the casing is initially inserted into the urethra so as to insure the position of the balloon 8 relative to the prostate gland. In addition radioopaque markers 136 can be optionally provided at opposite ends of the balloon where they are respectively attached to the casing and tip section so that the opposite ends of the balloon 8 can easily be seen fluoroscopically when inserting the balloon into the urethra. The tip section includes a screw drive fitting 138 formed so as to face the interior of the balloon 8 so as to receive the screwdriver configured end of a flexible stylet 140 adapted to function as an insertion guide and shown in place in Fig. 5. The stylet is adapted to extend though and create a seal with the water seal 116 prior to being pushed through the duck bill valve 120 into the casing 18. As previously mentioned, the balloon 8 is sized so that when inflated to the desired pressure within the prostatic urethra, the urethra of an averaged sized hypertrophied prostate gland will expand so as to compress the tissue by the balloon 8 without necessarily exceeding the elastic limit of the tissue, as such is required in a balloon dilation procedure. It is believed that an inflated outer balloon diameter of about 12mm is adequate for the average sized hyperthrophied gland to achieve the compression of the tissue, although this dimension may vary with smaller and larger prostate glands and the balloon may be sized accordingly. The balloon 8 may be made of various known materials already used in other medical procedures, such as those described in U.S. Patent No. 4,490,421, with polyethylene terephthalate (PET) being -21- preferred for the procedure for the prostatic urethra because of its relatively low modulus of elasticity (and therefore its non-compliant nature) and its transparency to both the laser radiation and 5 ultrasound beam. The material used for the balloon 8 for the prostatic procedure is preferably designed to accommodate approximately six atmospheres (approximately 90 psi) of water pressure and is adapted to hold that pressure for at least five 10 minutes. Preferably, the PET material is designed to rupture if the pressure well exceeds the six atmospheres (e.g., at eight atmospheres) in order to insure that ruptures at even greater pressures will not occur causing potential harm to the patient. It 15 should be evident that the material used for the balloon for other procedures in other body passageways may be of a type which is more compliant, such as a latex material, so as to more readily conform to the shape of the passageway, and may operate at other 20 pressures depending upon the balloon size and application. Finally, as shown in Fig. 4, a pair of small ultrasound transducers 10 and 12 are mounted adjacent one another on the remote end of the shaft 14. The 25 miniature transducers may be any type suitable for the application and may be of the type, for example, described in co-pending application U.S. Patent Application Serial No. 151,394 filed February 2, 1988 in the name of Michael A. Martinelli, assigned to the 30 present assignee and now U.S. Patent No. , issued . One of the transducers functions -22- as ultrasound transmitter 10 and transmits a beam of radiation at ultrasonic frequencies along the axis 144 which is transverse to the longitudinal axis of the shaft 14 into the area of the prostate of interest. 5 The other transducer positioned adjacent to the transmitter functions as the ultrasound receiver 12 and is adapted to receive ultrasonic echoes reflected from prostatic tissue exposed to the ultrasonic beam produced by the transmitter. The leads provided from 10 the two transducers are indicated at 150, which as previously described extend through the shaft to the pin connectors 88 of the control unit 4. It should be obvious that in some applications a single transducer can replace the two transducers 10 and 12, wherein the 15 single transducer would first function as a transmitter for generating the ultrasonic signal, and then function as a receiver for the returning ultrasonic echoes. As is well known, a standard T/R (transmitter/receiver) switch can be used to switch 20 the transducer between its transmit and reception modes in a manner well known in the art. An ultrasonic window 152 in the sleeve 16 is preferably provided through which the ultrasound beam is transmitted and echoes are received by the two 25 transducers, respectively. The oil provides a good ultrasonic coupling between the transducers and the water disposed in the balloon during the procedure. A reflector 156, reflective of the laser radiation provided by the laser beam delivery system, is 30 positioned relative to the fibers 104 so as to reflect the laser radiation along an axis 158 parallel and very close to the axis 144 of the ultrasound beam produced by the transmitter 10 (and as a practical matter the two axes are substantially coaxial with one another) . Referring to Fig. 7, the control unit 4 and catheter unit 6 are appropriately connected to power sources 160. A laser delivery system 162 is connected to the control unit using the connector 102. Preferably, the laser delivery system 162 includes a laser which provides a deeply penetrating continuous wave beam. A preferred example is a 100 watt neodymium-YAG laser because its radiation is not absorbed as strongly by tissue as some other lasers. The neodymium-YAG laser provides more pronounced scattering with deeper tissue effect occurring. See the Smith et al. article, supra. A source of pressurized fluid shown at 166 in Fig. 7 is connected to a suitable control valve 164 which is shown as controlled from the unit 4, although it may be separately controlled by the operator. The output of the valve is connected through the water port 118 of the control unit so that fluid can be introduced into the balloon 8. As the scanning motor 28 rotates the transmitting and receiving transducers 10 and 12 rotate about the axis 38. The angular position of the transducers 10 and 12 and the image information retrieved at each of a plurality of angular positions can be ascertained, processed, stored and displayed in a similar manner as described in co-pending U.S. Patent Application Serial No. 230,163 filed August 9, 1988 in the name of Michael A. Martinelli, assigned to the present assignee and now U.S. Patent No. . More specifically, the scanning motor 28 includes a shaft encoder 168 for indicating the angular position of the rotor shaft of the motor as the latter rotates about its axis. Control 4 is also connected directly to the processor controller 174 so that the former can be used to provide an actuation signal to the processor controller when the scanning motor is energized by the user. The rotational position of the rotor shaft is directly related to the pivotal position of the transducers 10 and 12 about the axis 38. The scanning motor 28, when energized, moves the transducers 10 and 12 through a predetermined angle, or continually rotates about the axis 38 in one or either rotational direction as controlled by the operator. The output of the shaft encoder can be a digital signal representative of the angular position of the transducers in finite increments. This output signal is applied directly to the processor controller 174. The processor controller 174 is also connected to provide signals to the transducer 10 for generating the acoustic signal along the signal generating axis 144 in response to the initiation signal provided by the user. The receiving transducer 12 receives reflected signals from targets substantially along or parallel to the axis 144. Transducer 12 is connected to the input of amplifier 170, which can be positioned on assembly board 58. Amplifier 170 boosts the signals provided by the receiving transducer in response to the reflected acoustic signals. Amplifier 170 is in turn connected to the input of an analog-to-digital (A/D) converter 172 (also provided on the assembly board 58) , which converts the analog output of the amplifier 170 to a digital signal. The sampling rate of the A/D converter is provided by processor controller 174 through the control line 176. The digital signal at the output of A/D converter 172 is applied to the coherent averager 178. The latter is provided to average the signals received from the A/D converter since the latter may represent several overlapping reflected signals detected by the receiving transducer 12. The average signal is applied to the processor controller 174. Processor controller 174 correlates the signal provided by the shaft encoder and the signal provided from the coherent averager corresponding to the current pivotal position of the transducer assembly. The two values are then stored in memory 180 and are displayed by the display device 182. Preferably, the values can be displayed as a two dimensional echogram through a predetermined scanning angle (e.g., up to 360°), or alternatively in some matrix arrangement with, for example, the angular position of the transducers about the axis 38 providing one axis of the display and the echogram detected being displayed along the other axis (the latter axis therefore representing distance from the receiving transducer 12 along the axis 144) . In this way the data will be spatially correlated with the incremental angular positions of the transducer assembly from which the data was received so as to create a mapped or composite image of the portion of the body viewed during the scanning of the transducer assembly through a slice of the viewed object in a plane normal to the axis 38. In operation, the instrument thus described is used to carry out the preferred prostatic urethral dilation procedure. More specifically, the linear adjustment assembly 110 which is secured to the outer casing 18 of the catheter unit is fitted with the stylet 142 by inserting the latter into the casing and securing the stylet by securing the end 140 of the stylet into the screw drive fitting 138 in the tip section 132 as best shown in Fig. 5. The stylet will insure that the balloon 8 can be inserted up the urethra into the prostate without folding on itself. The patient is appropriately anesthetized, as for example, with a topical anesthesia, such as lidocaine hydrochloride, applied liberally within the urethra. An additional mild sedative and prophylactic antibiotics can also be given. The penis is then appropriately prepped and draped and the casing with the stylet is inserted through the urethra 170 as illustrated in Figs. 8, 9 and 10. The clinician can feel the bulge 134 transrectally to insure that the balloon 8 has advanced into the prostatic urethra of prostate 172, past the external sphincter muscle 174, before the balloon is inflated so as to minimize the risk of damage to that muscle when the balloon is inflated. The maneuver can also be observed fluoroscopically by observing the radioopaque markers to insure precise positioning of the balloon 8. Once the balloon is properly positioned pressurized water (at a pressure up to 6 atmospheres) is introduced through the water port 118 so as to fill the casing 18 and inflate the balloon 8 to its maximum diameter as seen best in Fig. 10. Inflating the balloon 8 should compress the tissue so as to improve hemostasis and allow for more uniform laser radiation absorption of the tissue. With the balloon in place, the stylet 140 can be detached from the fitting 138 of the tip section 132 and withdrawn. It will be appreciated that as the stylet is withdrawn it will be pulled through the duck bill valve 120 which will then close before being withdrawn from the water seal 116 so as to substantially maintain the water pressure within the casing 18 and balloon 8. The shaft and sleeve 14 and 16 are previously secured to the control unit 4 with oil provided through fill port 92 and the transducers fixed in front of the window 152. In addition, the rack gear 122 is already fixed to the nozzle assembly 60, while the pinion gear 124 is previously secured to the housing 112, which in turn is fixed to the casing 18. The probe formed by the shaft and sleeve are threaded through the water seal 116 and through the duck bill valve 120. The latter will permit the entry of the probe, while the seal will prevent significant leakage of the water so that the balloon will remain inflated. The probe can be moved all the way so that the transducers 10 and 12 are disposed within the balloon 8 and the pinion gear 124 engages the rack gear 122. The position of the transducers can be confirmed by viewing the end of the shaft and sleeve fluoroscopically to be sure it is properly positioned between the two radioopaque markers 136. Exposure of selective tissue of the prostate to the laser beam can now be carried out. Preferably, tissue is exposed to the laser beam at one selected radial angle about the longitudinal axis 38 of the shaft 14, while longitudinally moving the shaft along the axis 38. Specifically, the probe formed by shaft 14 and sleeve 16 is moved longitudinally in the casing 18 until the transducers 10 and 12 and reflector 156 are positioned near one end of the prostatic urethra. The laser is energized while simultaneously moving the probe, and therefore transducers and reflector along the longitudinal axis 38 so as to expose tissue receiving the laser energy to a select amount of radiation sufficient to cause the tissue to be denatured. Longitudinal movement is achieved by the clinician by rotating the pinion gear 124 so as to move the rack gear 122. The transducers are used to view the tissue ultrasonically while and after the tissue is exposed in order to determine the area and extent of denaturization. The ultrasonic image can be viewed on the processor and monitor system 164. If desired this radiation and viewing step of the procedure can be repeated at one or more different angles to the longitudinal axis by manually rotating the transducers and reflector. The laser can then be energized while simultaneously moving the transducers and reflector along the longitudinal axis 38 so as to expose the new tissue receiving the laser energy to a select amount of radiation sufficient to denature the tissue. The result might be the pattern shown in Fig. 11B, where the denatured tissue is darkened as indicated at 200. Once all of the selected areas are exposed to the laser radiation, the water pressure can be released at water port 118 so as to deflate the balloon, and the entire instrument withdrawn from the urethra. As soon as the balloon is deflated bodily fluids will flow into the previously compressed and denatured tissue promoting healing of the damaged tissue. During post operative healing the denatured tissue will shrink causing the internal wall of the urethra to take on the scalloped contour as shown in Fig. 11C. This effectively results in the post-operative dilation of the prostatic urethra. The foregoing instrument and surgical technique are believed to provide several advantages in the treatment of symptoms of BPH. It is believed that the procedure will substantially reduce the length and degree of post-operative care currently required for the TURP procedure since it is currently estimated that the entire procedure described herein can be carried out on an out-patient basis, or require hospital care on a single overnight basis. Further, by denaturing the tissue it is believed that the procedure will substantially eliminate or at least reduce post-operative bleeding and trauma. It is believed that the procedure will reduce the chances of tissue damage associated with impotence and muscle damage associated with incontinence. The entire procedure is performed without the need of hormonal -30- treatments or long term heat therapy. Further, by inflating the balloon sufficiently to squeeze the tissue so as to compress the tissue without necessarily exceeding its elastic limit, the tissue will not be unnecessarily damaged due to tearing. Finally, the ultrasound transmitter and receiver 10 and 12 are positioned transurethrally so as to make the procedure much more controllable because of the proximity of the transducers to the tissue and the ability of the clinician to view the tissue being exposed to the laser radiation in real time. It should be evident that while the preferred embodiment of the method and instrument have been described for use in transurethral prostatic surgery for reducing the symptoms of BPH, the present invention can be used to treat any type of tissue, such as tumors, as well as used in other parts of the body. For example, the instrument can be used for removing tumors found in the prostate because such tumors are usually identifiable ultrasonically. The balloon can be used to compress the tumor and the laser beam can be subsequently used to denature the tissue of the tumor. The instrument and technique can be used in other parts of the body for treating tissue such as hemorrhoids. In the latter situation the hemorrhoids would be compressed so as to force blood from the hemorrhoidal tissue and so as to make the tissue more hemostatic as well as provide more uniform absorption of the laser energy. The hemorrhoidal tissue can then be denatured by the laser beam. In this application the balloon used should be preferably ore compliant than the type used in the prostatic procedure described above. Since certain changes may be made in the above apparatus and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted in an illustrative and not in a limiting sense.

Claims: WHAT IS CLAIMED IS: 1. An instrument for use in effectively dialating any constrictions of a passageway through a portion of a body part so as to relieve the symptoms associated with such constrictions, the instrument comprising: means for compressing the tissue of at least selected portions of said body part so as to enhance he ostasis; and means for denaturing at least selected portions of said compressed tissue so that as said denatured tissue heals the denatured tissue tends to shrink so as to effectively post operatively dilate the internal diameter of said passageway. 2. An instrument according to claim 1, wherein said means for compressing said tissue includes means, adapted to be inserted into said passageway, for at least temporarily exerting pressure outwardly from within said passageway on said tissue. 3. An instrument according to claim 2, wherein said means for compressing includes an inflatable balloon, means for moving said balloon into said passageway, and means for inflating said balloon. -33- 4. An instrument according to claim 3, wherein said body part is the prostate gland and said balloon is sized so that when inflated within said passageway, the pressure on said tissue will not exceed the elastic limit of the tissue of an averaged sized hyperplastic prostate gland. 5. An instrument according to claim 2, wherein said means for denaturing said tissue includes means for transmitting a beam of radiation along a transmission axis into selected portions of said compressed tissue. 6. An instrument according to claim 5, wherein said means for transmitting said beam of radiation includes means for directing said beam from within said passageway at an angle transverse to the elongated direction of said passageway. 7. An instrument according to claim 6, wherein said means for transmitting said beam includes fiber optic means for transmitting said beam into said passageway and reflector means for reflecting said beam at said transverse angle along said axis. 8. An instrument according to claim 7, wherein said means for denaturing said tissue further including means for moving said reflector means so as to move said transmission axis through select portions of said tissue. 9. An instrument according to claim 8, wherein said means for compressing includes an inflatable balloon made of a material substantially transparent to said beam of radiation, means for moving said balloon into said passageway and means for inflating said balloon, and said means for moving said reflector means includes means for moving said reflector along the passageway within said inflated balloon. 10. An instrument according to claim 9, further including means for rotating said reflector means within said inflated balloon about the elongated direction of said passageway so as to position said axis at select angles to said elongated direction of said passageway. 11. An instrument according to claim 10, further including means for observing said tissue from within said passageway in substantially the same direction as said axis of said beam as said tissue is exposed to said beam. 12. An instrument according to claim 11, wherein said means for observing said tissue from within said passageway includes transducer means positioned adjacent to and movable with said reflector means for transmitting a second beam into said tissue and means for receiving reflections of said second beam from said tissue. 13. An instrument according to claim 12, wherein said transducer means includes a pair of transducers secured within a shaft and said reflector means includes a reflector fixedly secured relative to said shaft adjacent said transducers. 14. An instrument according to claim 13, wherein said balloon is secured to a casing and said shaft is movable within said casing so that said transducers and reflector are movable within said balloon. 15. An instrument for use in effectively dilating a prostatic urethra of a prostate gland so as to relieve the symptoms of prostate enlargement, the instrument comprising: means for compressing the tissue of at least selected portions of said prostate gland so as enhance hemostasis; and means for denaturing at least selected portions of said compressed tissue so that as said denatured tissue heals the denatured tissue tends to shrink so as to post operatively effectively dilate the internal diameter of the prostatic urethra. 16. An instrument according to claim 15, further including means for observing said selected portions of said compressed tissue from within said prostatic urethra as said select portions of said compressed tissue are denatured. 17. An instrument according to claim 16, wherein said means for compressing said tissue includes means, adapted to be inserted into said prostatic urethra, for at least temporarily exerting pressure outwardly from within said prostatic urethra on said tissue. 18. An instrument according to claim 17, wherein said means for compressing includes an inflatable balloon, means for moving said balloon into said prostatic urethra and means for inflating said balloon. 19. An instrument according to claim 18, wherein 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. 20. An instrument according to claim 18, wherein said means for denaturing said tissue includes means for transmitting a beam of radiation along a transmission axis into selected portions of said compressed tissue. 21. An instrument according to claim 20, wherein said means for transmitting said beam of radiation includes means for directing said beam from within said prostatic urethra at an angle transverse to the elongated direction of said prostatic urethra. 22. An instrument according to claim 21, wherein said means for transmitting said beam includes fiber optic means for transmitting said beam into said prostatic urethra and reflector means for reflecting said beam at said transverse angle along said axis. 23. An instrument according to claim 22, wherein said means for denaturing said tissue further including means for moving said reflector means so as to move said transmission axis through select portions of said tissue. 24. An instrument according to claim 23, wherein said means for compressing includes an inflatable balloon made of a material substantially transparent to said beam of radiation, means for moving said balloon into said prostatic urethra and means for inflating said balloon, and said means for moving said reflector means includes means for moving said reflector along the prostatic urethra within said inflated balloon. 25. An instrument according to claim 24, further including means for rotating said reflector means within said inflated balloon about the elongated direction of said prostatic urethra so as to position said axis at select angles to said elongated direction of said prostatic urethra. 26. An instrument according to claim 25, wherein said means for observing said selected portions of said compressed tissue includes means for observing said tissue in substantially the same direction as said axis of said beam as said tissue is exposed to said beam. 27. An instrument according to claim 26, wherein said means for observing said selected portions of said compressed tissue includes transducer means positioned adjacent to and movable with said reflector means for transmitting a second beam into said tissue and means for receiving reflections of said second beam from said tissue. 28. An instrument according to claim 27, wherein said transducer means includes a pair of transducers secured within a shaft and said reflector means includes a reflector fixedly secured relative to said shaft adjacent said transducers. 29. An instrument according to claim 28, wherein said balloon is secured to a casing and said shaft is movable within said casing so that said transducers and reflector are movable within said balloon. 30. A method of effectively dilating any contricted portions of a body lumen so as to relieve the symptoms associated with such constrictions, said method including the step of: denaturing at least selected portions of the tissue forming said lumen at said constrictions so that as said denatured tissue heals the denatured tissue tends to shrink so as to effectively dilate the lumen. 31. A method according to claim 30, further including the step of compressing the tissue of at least selected portions of the tissue forming said body lumen so as to enhance hemostasis prior to said denaturing step. 32. A method according to claim 31, wherein said step of compressing said tissue includes the step of at least temporarily exerting pressure outwardly from within said lumen on said tissue. 33. A method according to claim 32, wherein said step of compressing includes the steps of moving an inflatable balloon into said passageway and inflating said balloon. 34. A method according to claim 33, wherein said lumen is the prostatic urethra of a prostate gland, and said step of inflating said balloon exerts a pressure on said tissue at a level which will not exceed the elastic limit of the tissue of an averaged sized hyperplastic prostate gland. 35. A method according to claim 33, wherein said step of denaturing said tissue includes the step of transmitting a beam of radiation along a transmission axis into selected portions of said compressed tissue. 36. A method according to claim 35, wherein said step of transmitting said beam of radiation includes the step of directing said beam from within said lumen at an angle transverse to the elongated direction of said lumen. 37. A method according to claim 36, wherein said step of transmitting said beam includes the steps of transmitting said beam into said lumen and reflecting said beam at said transverse angle along said axis. 38. A method according to claim 37, wherein said step of denaturing said tissue further includes the step of moving said reflected beam so as to move said transmission axis through select portions of said tissue. 39. A method according to claim 38, wherein said step of compressing includes the step of moving an inflatable balloon into said lumen and inflating said balloon, and said step of moving said reflected beam includes moving said reflected beam along the lumen within said inflated balloon. 40. A method according to claim 39, further including the step of rotating said reflected beam within said inflated balloon about the elongated direction of said lumen so as to position said axis at select angles to said elongated direction of said prostatic urethra. 41. A method according to claim 40, further including means for observing said tissue from within said lumen in substantially the same direction as said axis of said beam as said tissue is exposed to said beam. 42. A method according to claim 41, wherein said step of observing said tissue from within said lumen includes the steps of transmitting a ultrasonic beam into said tissue from within said lumen, receiving reflections of said ultrasonic beam from said tissue, and forming an image of said tissue from said refleetions. 43. A method according to claim 42, wherein said step of observing said tissue from within said lumen includes the step of moving said beam of radiation with said ultrasonic beam during said denaturing step. 44. An instrument for use in effectively dilating the prostatic urethra so as to relieve the symptoms of an enlarged prostate gland, the instrument comprising: a catheter casing sufficiently long so that a portion can be inserted into said prostatic urethra; an inflatable balloon supported on said portion of catheter adapted to be inserted into said prostatic urethra, said balloon being sized so that when inflated within the prostatic urethra at least selected parts of said prostate are squeezed so as to compress the tissue of said selected parts and improve the uniformity of energy absorption to selected laser radiation; a probe axially and rotatably movable within said casing; means, fixed relative to said probe, for transmitting a beam of said selected laser radiation transverse to the elongated direction of said prostatic urethra into at least portions of said tissue of said selected parts of said prostate so as to denature said tissue portions so that as said tissue portions heal the prostatic urethra is effectively dilated; and means, fixed relative to said probe, for observing said portions of said tissue of said selected parts of said prostate as said portions are exposed to said laser beam. 45. An instrument according to claim 44, further including means for transporting water within said casing to said balloon for inflating said balloon and maintaining said balloon in an inflated state with said water. 46. An instrument according to claim 45, wherein 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. 47. An instrument according to claim 46, wherein said means for transmitting said laser beam includes fiber optic means for transmitting said beam into said prostatic urethra and reflector means, fixed relative to said probe, for reflecting said beam at transverse angle to said elongated direction of said prostatic urethra. 48. An instrument according to claim 47, further including means for moving said probe relative to said casing so as to move said laser beam through said selected portions of said tissue. 49. An instrument according to claim 48, wherein said means for moving said probe relative to said casing includes means for moving said probe along the elongated axis of said casing. 50. An instrument according to claim 49, wherein said means for moving said probe relative to said probe further includes means for rotating said probe about its elongated axis relative to said casing so as to rotate the direction of said laser beam. 51. An instrument according to claim 47, wherein said means for observing said 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. 52. An instrument according to claim 51, 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.

Inventors: MARTINELLI MICHAEL A, ROTH ROBERT A, MARTINELLI, MICHAEL, A., ROTH, ROBERT, A.
Applicants: INTRA SONIX INC, INTRA-SONIX, INC.
Application year: 1990
Main classification: A61N5
IPC codes: A61B17, A61B18, A61B19, A61M25, A61M29, A61N5