CA2127102A1

CA2127102A1 - Tissue ablation and a lateral-lasing fiber optic device therefor

Info

Publication number: CA2127102A1
Application number: CA002127102A
Authority: CA
Inventors: Douglas E. Johnson; Hany M. G. Hussein; Marvin P. Loeb
Original assignee: Individual
Current assignee: Trimedyne Inc
Priority date: 1991-12-30
Filing date: 1992-12-29
Publication date: 1993-07-08
Also published as: JPH07505065A; EP0623007A4; US5437660A; WO1993012728A1; EP0623007A1

Abstract

A method for removing unwanted material in a body lumen, cavity or organ provides the steps of using an endoscope or other viewing sytem to position a suitably sized lateral-lasing fiber optic device (14) axially at one or more places in a body lumen, cavity or organ and delivering a predetermined amount of light energy for a predetermined period of time laterally in one or more directions, while delivering a biocompatible fluid at a predetermined rate of flow. The distal end of the lateral-lasing fiber optic device (14) includes a reflectively-coated metal tip (15), which is capable of directing, by reflection, the light energy from the optical fiber laterally from the longitudinal axis of the light energy carrying optical fiber and outwardly toward a target tissue region.

Description

: W~g3/12728 2 1 ~ 7 ~ ~3 2 P~T/US92/11368 , ~ . ., TISSUE ABLATION AND~ L~ LASING
FIBER OPTIC DEVICE THEREFOR
Field Of The Invention The present invention relates to medical procedures and de~ices for ablating or coagulating , tissue to effect the removal of unwanted material from body lumens, including blood vessels or ducts, c~vities . or organs, and more particul~rly to ~a) transurethral laser resection of the prostate to remove unwanted tissue and increase urine flow, (b) coagulation or a~lation of the endometrial lining of the utexus to stop excessive bleeding, (c) coagulation of bleeding blood ; vessels and (d) coagulation or ablation of tumors.
: Backqround Of The Inven _on Treatment of benign prostatic hyperplasia is one of this natlon's ma jor health-caxe expenses, as evidenced by the fact that transurethral resection of, the prostate is second only to cataract extraction as.
the ma jor operation most costly to Medicare . For the approximately 450, 000 prostatectomies performed annually .~
!, in the United States, hospitalization expenses and physician charges (not including costs for nonoperati~e evalua~ion and treatment) approach ~ive billion dollars.
The surgical procedure constitutes over a third of the ;~25 major operations perfoxmed by urologists, and the operatiYe and the clînical activities associated with it involve nearly a qu rter of the urologist~s time.
Mortality for the pr.ocedure has been reduced to 0.2~
over the last 27:years, but the incidence of immediate 30 ~ postoperative morbidity has remained unchanged at 18~.
The high cost of the procedure, not only in physician ~: time but also in medical expense and patient morbidity, `~ has therefore caused urologists to seek chaaper and less morbid ways of treating patients with benign prostatic hyperplasia.

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W~93/12728 ~ 7 ~2 PCT/US92/ll

- 2 -During the last decade, as a result, a variety of alternative treatment methods have been introduced, ,...
including watchful waiting, medical management using alpha blockers or androgen suppression, insertion of prostatic stents and coils, balloon dilation, prostatic hyperthermia, and transurethral incision. None of these methods has proved superior to transurethral resection, and the majority of patients with bladder-outlet obstruction continue to require hospitalization for this ~' 10 procedure ~o xelieve their symptoms.
The procedure of transurethral resection includes the step of electrically heating an insulated ~ loop of wire in a elec~rocautery de~ice and slowly L.;i drawing the heat~d lo~p back and forth longitudinally within the prostate to cut and cauterize tissue, creating a series of furrows along the length of the prostate until the lumen has ~een treated circumferentially. This procedure typically takes 45-60 minutes of physieian's time to perform and considerable skill. If areas are missed or inadequately treated, an unxatisfactory treatment may result. ~lycine,sorbitol-manni~ol solution or sterile water, which are not as physiologicall;y biocompatible as saline, are used as a cooling fluid, because saline will short-circuit the ~,: .
electrical power used to heat the loop and can cause harm to the patient.
Transurethral reseetion typically results in three to six days of bed stay at considerable cost, one to two weeks of reçuperation time, substantial psst-operative pain and bleeding, and approximately 10% ofthe patients require a blood transfusion. Up to 5% of ~; the men who underg~ this procedure suffer incontinence, and impotence results in up to 15%.
Although transurethral laser prostatectomy has

3~ - held great theoretical interest, it has heretofore been ~ ~ .

~93~1~728 ~ 2 ~ ~ ~ 2 PCl/US9~/11368 impractical because of the difficu~ties in simply, accurately and effectively directing light energy into the tissue of the prostrate. Urologists have attempted to apply laser photo irradiation for treatment of prostatic disease. McPhee, in Lasers in Uroloq_c Surqery, 2d ed., Year Book Medical Publishers, Inc., Chicago, IL ~1989), pp~ 41-49 and in Lasers in Urolo~ic SurqerY, Year Book Medical Publishers, Inc., Chicago, IL
(19~5), pp. 94-102 describes employing light energy from a neodymium:YAG laser following transurethral prostatectomy in order to improve hemostasis and reports satisfactory postoperative voiding patterns. However, his technique was relatively cumbersome. Moreover, McPhee reports that he encountered some difficulty controlling bleeding of larger vessels at the ~esical neck. Beisland and Sander, Urol. Res. l2:2~7-259 ~l984) describe using light energy from a neodymium:YAG laser via a flexible laser cable three to four weeks after onventional transurethral prostatectomy in order to treat localized~prostatic cancer, but report that it was found necessary to insert the flexible laser cable into the prostatlc cavity through a suprapubic trocar cystoscope. While the procedure was well tolerated and ~oid of serious complications, and while the preliminary results were~encouraging, a surgical incision, albei~
smallt is still necessary, with the attendant risk of infec~ion and extended hospital bed stay.
U.S. Patent No. 4,445,892 to Hany M. Hussein, Marvin P. Loeb ~nd Harvey S. Weiss ~eaches a dual ~30 balloon catheter device which is provided with two spaced and expandable balloons for occluding a segment of a blood vessel between the balloons. The dual balloon catheter device also includes a first channel for flushing the occluded segme~t, an optical system for use in the segment, a longitudinally movable and ,~, ~ WO93/12728 PCT/US92/11368 2~Z~

- 4 -rotatable mirror or prism for directing light energy at ~ an angle of 90 to the axis of the catheter, and a .
second channel for introducing fluid into the blood vessel distally of the device. Such a device is likely to require the same 45-60 minutes of procedure time and a high level of operator skill.
U.S. Patent No. 4,672,963 to Israel Barken teaches a surgical system for destroying unwanted internal structures which includes a laser device, an .:~
ultrasonic probe and a computer system. The ultrasonic probe provides data~signals that are processed by the computer system-to pro~ide an image of the structures involved in the laser irradiation procedure. ~he laser device can be~inse~rted in the body and, while moving through the obstructed lumen, is acti~ated by the computer system to provide radiation ~apable of destroying internal tissue. By calibrating the effects ~; ~ of the laser device~as a~function of power, the surgical ~, ~ procedure ~can be~controlled by including overlaying ~; ~ 20 images~of the regions already~affected~by the surgical ~; proc~edures~on the~images;previously provided by the uItrasonic pro~ .~ This~ image reconstruction can be per~ormed in r~eal time~providing immediate fee ~ ack to the~attending physician. The computer system can also 2S ~monitor system~parameters such~as laser power. This system~has particular ap*lication to procedures involving the prostate~gland where the laser device can be inserted intraurethrally and the ultrasonic probe can be inserted~intraurethrally or transrectally. However, ~ 30 ~ this techni~que~requires expensive equipment and, like ;~ conventional transurethral resection of the prostate, takes considerable~time and skill.
V.~S. Patent No. 4,955,882 to Said I. Hakky ~: ~ teachés a ~esectoscope for prostate surgery which includes a rotating cutting element mounted within an : :
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~ W ~93/12728 PCT/U592/11368 2~7~ 2 _ 5 _ outer sheath adapted to be inserted into the urethra.
The cutting element has helical threads along the length thereof and a cutting blade at its distal end. ~The outer sheath has a covered distal end portion which extends beyond and over the cutting blade and has an opening therethrough adjacent the cutting blade. Within the outer sheath is an inner sheath surrounding the cutting element except for the cutting blade. .An optical fiber which is optically coupled to a laser is positioned within the space between the inner and outer sheaths and extends along the length of the inner sheath - to a position adjacent the cutting blade. The optical fiber is surrounded by a third sheath and is adapted to be moved by the rotation of the cutting element so that the beam of light en~rgy from the optical fiber advances through tissue to cut and coagulate the resected area ; before the cutting blade of the cutting element reaches the resected tissue. Irrigation fluid is pro~ided to the area between the inner and outer sheaths and is withdrawn through~the inner sheath. A telescope is also provided through the cutting element of re~iewing the area being~resected. The lack of accuracy of such a cutting device, with the risk of damage to the bladder sphincter,~perforation of the prostate and damage to the ~rectum and intest~ines, makes this device less desirable ~ than conventional electrocautery resection.
i~ U.S.~patent;No. 4,449,528~to David C. Auth, Dale M. Lawrence and Tim R. Majoch teaches a miniaturized,~endoscopically deliverable thermal cautery probe ~for cauterizing internal vessels. The probe is applied to tiss~es cold. Thereafter, a xelatively large number of electric heating pulses of equal energy is then applied to an internal heating eIement in the probe. The probe has an internal heating element in ~ ~ 35 direct thermal contact with an active heat-transfer ,.~ ~

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'~12~Q~ - 6 -' portion that has a low heat capacity to insure quick ~ heating and subsequent cooling, thereby adequately ;~ coagulating tissue while minimizing heat penetra~ion and resulting tissue damage. The electrical power applied to the probe is continuously measured and is terminated when the energy delivered reaches a preset value. The number of such pulses applied to the probe, hence the total energy delivered, may be present whîle the duration of the period during which the pulses were applied is displayed. Alternatively, the duration of the period during~which such pulses applied, hence the total energy delivered, is displayed. The heating i~
element for the probe is a controlled breakdown diode which as a breakdown~voltage that is a function of its temperature~so that the temperature can be controlled.
Again, glycine is used as a cooling fluid, since saline cannot be used in the~ presence of an electrical device.
The heating element has a resistance of greater than 0.5 . ~ . .
ohm to provide adequate power dissipation with relatively low currents. A washing fluid, preferably ~- flowing along the outside of the~probe toward its tip, ;~ cleans blood from~ the tissue to be ~eoagulated to make the source of~lood more readily visible. The risk of excessive heat~penetration from such a device to the ~rectum~and~intestine~makes this~device less desirable than conventional electrocautery resection.
U.S~.~;Patent~ No. 4,672,961 to David H. Davies teaches an apparatus and method for retrola5ing plaque deposi~s in a coronary artery to remove the same, which includes a tip assembly on the end of a flexi~le inner tube containing optical fibers that are slidable along a . ~ ~
i ~ guide wire. The top assembly includes a reflective surface rearwardly of a front face that directs light energy supplied through the optical fibers in a rearward direction through a window portion to a focal point : :~:

;~ W~-~3~12728 PCT/US92/11368 2~ ~J7.~ ~2 ~ 7 -~.
externally of the tip assembly. The deposit is removed as the top asse~bly is moved in a rearward progression back through the deposit. Such a device entails the . same to and frsm, longitudinal movement and periodic rotation as electrocautery resection to produce a circum~erential result, requires a similar 45-60 minute . procedure time and entails significant operator skill, without predictable results.
. U.S. Patent No. 4,646,737 to Hany M. Hussein and Marvin P. Loeb teaches a heat applying medical , device for applying localized heat to a portion of a patient's body. Generally, the heat applying medical 1' ~
. de~ice includes a light transmitting condui~ and a heat ,;i.. generating element which converts transmitted li~ht into ~, 15 heat. A suitable exterior tube can also be provided for ; guidance, streng~h and delivery of fluids. The heat j:! applying medical device can be used to cauterize or ;l destroy tissue, or alter or remove deposits from lumens.
~ The heat applying medical device can also serve as part A ~ 20 of a system which provides the light and measures the tempera~ure of the element. While this device produces localizèd heat;ing and ablation of tissue, the risk of .~. heat penetrat:ion:i~nto adjoining tissues and organs makes !~, , it less desirable than conventional electrocautery i~ : 25 resection.~
t~!~ ~ Endometrial ablation of the uterus in females, ,~,i using an electrocautery, like in resection of the prostate, involves slowly moving an electrically heated : wire loop al~ng the inner wall of the uterus under direct vision, cutting and coagulating tissue in ~ ~ fur~ows, until the entire inner surface of the uterus .~ has been treated. The procedure generally takes 45-60 ; minutes of physician time and considerable skill. In addition to significant pain and bleeding, substantial : 35 fluid flow is required to distend the uterus, which can ;
; ~
,..'i WOg3/l2728 PCT/US92/1l36~
2 ~ 1 cause excess absorption of fluid by tissues and leakage into the abdominal cavity, with risk of infection. If an area is missed or inadequately treated, an unsatisfactory treatment may result, and inadvertent .~ 5 perforation of the uterus could be extremely dangerous to the patient.
~: U.S. Patent No. 4,834,091 to Douglas E. Ott teaches a surgical ~echnique which uses a neodymium:YAG
laser to treat the uterus while the uterus is kept distended ~y the flow of saline into the uterine cavity.
The surgical technique includes the hysteroscopic insertion of a retrievable ostial plug into the tubal ostia of each fallopian *ube so that the saline does not ~: ~ flow through the fallopian tu~es during the period of : ~ 15 time in which~the laser is used to treat the uterus. At : the conclusi:on of the }aser treatment, the retrievable ostial plugs are hysteroscopically retrieved and withdrawn~ Such a system entails an even longer period of time and special skills in the placement of the ostial plugs:, with little improvement in procedure safety.
U~S. Patent No. 4,836,189 to Jimmie B. Allred, III, Richard:A~ Kokos:a, AIlan I.:Krauter and Richard W.
Newman tsaches~a ~ideo hysteros~ope which has an elongated flexible~insertion tube~ containing a video im~ging:head at ~its~distal end, with a channel for a surgi:cal laser fiber and;a~saline channel which emits a : cont~inuous stream of saline solution distally from the head. The articulation section is kept as short as possible, and is limited to a maximum deflection of about 30 degrees. This system again requires significant operator skill and 45-60 minute of procedure time, and the limited 30 angle of deflection does not ~ permit some portions of the uterus to ~e treated, ::
~, ~ .
~' W~93/12728 ~ 12 rs 1 ~ 2s PCT/US92/11368 _ g _ .' resulting in an incomplete procedure and potential regrowth of the endometrium.
Summarv Of The Invention The present invention provides a relatively simple, low-risk, virtually bloodless, painless and rapid method for ablation and coagulation of tissue to effect the removal of unwanted material in a body lumen, ca~ity or organ using a lateral-lasing fiber-optic device under endoscopic or other viewing. Another advantage of the present invention is that it provides a lateral-lasing fiber-optic device using light energy from a laser, instead of electrical energy from an electrocautery device, to perform various medical 3i procedures, such as transurethral laser resection of the prostate to remove unwanted tissue and increase urine ~ flow and ablat~ion of the endometrial lining of the ,`i ~ uterus to stop escessive bleeding.
.ii The method contemplated by the present ~; invention utillzes an endoscope or like viewing device to position i~n a~body lumen, ca~ity or organ a lateral-; lasing fiber-optic device. This lasing device preferably~has a reflectively coated metal tip at its distal end. The coated metal tip is capable of directing by reflection the light energy emitted from the optical~ fiber laterally from the axis of the optical fiber, and delivering`a predetermined amount of light energy for a predetermined period of time in one or more directions, without substantial to-and-from longitudinal movement of the lateral-lasing fiber-opt~c device, while delivering bicompatible fluid at a predetermined rate of flow to control the temperature of the metal tip and the target tissue. The unwanted tissue is partially a~lated and the remainder is coagulated to the desired depth~
As a result, thermal necrosis and ultimate absorption or dissolution of the unwanted material is achieved.
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:~ s ~ W~3/1272~ P~T/US92/1136~
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Prior to laser irradiation the tissue to be irradiated may be infused with a photoactive agent.
.~3 Brief Descri ~ n Of The Drawinq~
In the drawings, FIG. 1 is a fragmentary, ~l 5 schematic view of a laser and a lateral-lasing fiber-:3 optic device, in which an optical fiber, opticallv and mechanically coupled to the laser, extends through an endoscope to a reflectively coated metal tip at the distal end of the optical fiber, and which has been ~ 10 constructed in accordance with the principles of the $~ present invention;
FIG. 2 is an expanded, fragmentary, cross-sectional view of the lateral-lasing fiber-optic device of FIG. l;
FIGS. 3, 4, 5 and 6 are cross-sectional views showing alternative embodiments of the lateral-lasing fiber-optic device of ~IG. I in which the laser enexgy beam emitting cavi~y is protected by an operculum, i.e., a covering;
FIG. 7 is a schematic representation of the ~pproximate, substantially circular damage zone contour . ~ in a potato model following the delivery of 40 watts of ~; light energy~ from a neodymium:YAG laser through a lateral-Iasing fibe-optic device for 60 seconds in each :~ 2~ o~ the 12, 3, 6 and 9 o'clock positions;
si ~ FIG. 8~is a schematic representation of the approximate, substantially oval damage 20ne contour in a potato model following the delivery of 40 watts of light energy from a neodymium:YAG laser through a lateral-lasing fiber-optic device for 30 seconds in the 12 and 6 ~ ~ o'clock positions and 60 seconds in the 3 and g o'clock ;~ positions;
FIG. 9 is a schematic representation of the . ~ approximate, substantially oval damage zone contour in a potato model following the delivery of 40 watts of light :

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energy from a neodymium:YAG laser through a lateral-lasin~ fiber-optic device for 6~ seconds in each of the 2, 4, 8 and l0 o'clock positions;
FIG. l0 is a schematic representation of the S appro~imate damage zones in a potato model following the delivery of 40 watts of light energy from a neodymium:YAG laser through a lateral-lasing fiber-optic ~ device for 60 seconds in each of the 3 and 9 o'clock '.~ positions;
FIG. l~l is a schematic representation of the ~, approximate damage zones in a potato model following the delivery of 60 watts of light energy for 60 seconds in the 3 o'clock position and 40 watts of light energy for 90 seconds in the 9 o'closk position; and FIG. 12 is a schematic representation of the ` approximate damage zones in a potato model following the delivery from a neodymium:YAG laser through a lateral-lasing fiber-optic device of 30 watts of light energy for 80 seconds in the 3 and 9 o'clock positions.
DescriE~ion Of_;~The Preferred:Em~ m~
: Refer~ring to FIG. l, a Iaser source l0 is :~ connected by~a light energy coupling device ll~
: consisting of:female and:maIe components (not shown), to an optical;fiber 12, which can extend through an ~t~ ~ 25 endosc~pe 13.~ ~A lateral-lasing fiber-optic device l4, ; ~ : which preferably~is provided at its distal end with a bulbous metal~:~tip 15, is connected to optical fiber 12.
The me~al tip can have any convenient configuration, howe~er. The metal tip lS is coated with a reflective material~ ~etal tip l~ sf lateral-lasing fiber-op~ic device 14 is shown in greater detail in FIG. 2. Optical fiber 2, at whose distal end is mounted metal tip 15, preferably coated in its en~irety with reflective material 26, is connected at its proximal end to laser source l0. Reflective surface layer 27 within ca~ity 23 :
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W~93/12728 PCT/US92/l1368 ~ - - 12 -;:', , of tip 15 may be flat, a parabola or otherwise curved and is positioned so that the region of reflective surface 27 directly opposite optical fiber 22 is ~ inclined at an angle, preferably of approximately 45 ,,,,~, .
from the longitudinal axis of optical fiber 22.
~ Reflective surface 27 receives laser light energy from ?~ optical fiber 22 and directs most of the recei~ed energy outwardly by reflection with divergence angles of approximately ~5 to 135, laterally from the axis of optical fiber 22. Preferably, the center of the arc or cone of the outwardly directed energy is about 90 from the longitudinal axis of optical fiber 22. The ~r' outwardly directed energy is designated by R in the FIGURES, while energy consumed by incidental heating of ~ ~ 15 the metal tip is designated by H. Temperature of the f~f ~ metal tip may be sensed and monitored by any convenient `~ temperature sensing means known in the art. See, for example, U.S.~Patent No. 4,646,737 to Hussein and Loeb.
The method of ablating and coagulating tissue ~; 20 to achieve, usually~;through vaporization and thermal f~ ~ necrosis, the removal of unwanted tissue or material in ,~ ~ a body lumen,~cav~ity or organ, can ~e effected by using ~iflff1 ~ ' an endoscope~l3 or other suitable viewing system to position in the~desired~place in a body lumen, cavity or ~ organ a lateral-la~sing fiber-optical device such as device 14 (FIG.~ while delivering to the irradiated region throughout the lasing procedure saline, a glycine ;~ solution, a~sorbitol-mannitol solution, sterile water or other b~ocompatible fluid at a predetermined rate to control the temperature of metal tip 15 as well as that of the target tissue. At the same time a predetermined - amount of light energy is delivered from a laser source for a~predetermined period of time in each of one or more directions, preferably in four equal or unequal sized quadrants, to achieve the desired zone of tissue ~ ~ :
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~, coagulation. This irradiation is carried out usually without substantial longitudinal movement of metal tip ~ 15 during the lasing, except as may be necessary to '~ maintain proper placement of the lateral-lasing fiber-optic device opposite the target tissue.
The viewing system for properly placing the lateral-lasing fiber-optic device 14 in the prostate or uterus, sr other body lumen, organ or cavity, ~ay be an endoscope, rigid or flexible, such as a cystoscope with ; 10 a diameter of about 21 to 25 French, preferably 23 French, or a hysteroscope, of conventional size.
magnetic resonance imaging system, an ultrasound im.aging system, an X-ray or fluoroscopic imaging system or any other suitable ~iewing system may also have utilized in lieu of or in addition to the aforementioned viewing systems.
~: In a preferred e~bodiment, the entire outer surface of metal tip 15, instead of only reflective surface 27~ is reflectively coated to minimize the amount of heat radiated by metal tip 15.
Preferably, tissue does not touch the light ~: ~ reflective surface 27 of metal tip 15 during lasing as : the tissue may adhere, disrupt the reflection of laser ~ energy and:~cause over heating of metal tip 15 ~y i~ 25 excessive absorption of light energy.
: In an alternative embodiment shown in FIG. 3 ~: ~ an operculum:~in the form of one or more, i re ~ ~ a plurality of, metal ribs 28 is positioned over cavity 30 to prevent tissue ~rom contacting reflectlve surface Iayer 37 of metal tip 25 mounted to optical fiber 32 Me~al ribs 28 can be made of platinum or stainless ~;~ steel, may be plated with gold, copper or silver for ;~i ~: enhanced light reflecti~ity and can have a round, semi-:~ circular, square, triangular or other cross section. If ~; 35 desired, a heat insulating layer can be provided between i ! '.

", W093/12728 PCT/US92/113~.
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;,, reflective surface layer 37 and metal tip 25. Moreover, reflective surface layer 37 need not be integxa with metal tip 25 but can be an inset as well.
FIG. 4 shows, in another embodiment, a transparent baffle or canopy 29, made of a material transparent to the light energy being used, which partially covers cavity 33 in metal tip 55 mounted to optical fiber 42 to prevent tissue from contacting reflective surface 42. Canopy 29 an be made of quartz, fused silica, heat resistant or fused silica and glass sold under the~tradename "Pyrex". Canopy 29 can also extend into cavity~33 and support an inset such as a mirror or a prism for directing light energy laterally outwardly from cavity 33.
In yet another embodiment, shown in FIG. 5, canopy 31 is transpar~ent and covers cavity 35 in tip 65 mounted to fiber optic 52 in its entirety, again to prevent tissue from contacting reflec$ive surface layer 57. If desired, a fluid port or vent port can be provided in canopy 31 :or tip 65.
The~presently contemplated tissue ablation device also can have~a tip design as~shown in FIG. 6 where tip 75~defines~cavity 76 and a through passageway 77~wi~h abutment~85~situated at an intermediate location within passageway 77.~ The proximal end of passageway 77 receives the~distal~end of optical fiber 62 while the dista~l~end;~of passageway 77 receives mounted therein a ~;~ cylindrical inset 79 ha~ing a reflective face 81 in juxtaposition to~the distal end face 83 of optical fiber ~ 62. Reflecti;ve face 81 is positioned relative to distal ` ~ end face 83 so as to direct laterally outwardly through cavity 76 preferably substantially all of the laser ~; - energy beam that is conveyed to tip 75 via optical fiber 62 and emanates from end face 83.
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Abutment 85 maintains a desired spacing between end face 83 of optical fiber 62 and reflective ~ face 81 o~ inset 79. ~ocking ring 87 holds inset 79 in ;~ place within passageway 77. To this end, groove 89 that circumscribes the interior wall of passageway 77 is ., provided. Locking ring 87 nests in groove 89 when inset v. 79 is in place.
Canopy 91, again an operculum transp~rent to laser energy beam that exits laterally from cavity 76, co~ers the cavity in its entirely and protects against the accumulation of tissue debris or the li~e . therewithin. Al~ernatively, in order to keep adjacent tissue out of cavity 76, one or more guard bars of the ~ type illustrated in FIG. 3 can be provided across cavity l~'J, ~ 15 76.
The temperature of the metal tips such as 15, . ~:~ 25, 55, 6~ and 75 can be controlled by a physiologically acceptable irrigation fluid that c2n be introduced through the endoscope, for example, and directed to flow past the metal tips while the laser source is energized.
The desired rate of fluid flow is about 20 to ~j. ~ about 200 cubic:centimeters per minute, ~refera~ly about ,~ : 50 cubic centimeters per minute. Preferably, the irrigation fluid is warmed to body temperature. This . ~ 25 : rat~ o~ flow i :preferably obtained by an irrigation :pump or, alternat:ively~ by utilizing a static pressure head, e.g., by~hanging a bag of the irri~atio~ fluid in an elevated position, usually approximately 2 to 4 feet ~: above the cystoscopy table, preferably 2 1/2 to 3 feet above the same~ and adjusting a flow adjusting device to !.''' ~ ' deliver t~e~desired flow rate.
;; ~ The lig~t energy for irradiation is generated by a laser, preferably a neodymium:YAG laser, but may be :~ chosen from any of a number of lasers, including a :~ 35 frequency-doubled neodymium:YAG laser, a KTP laser, an W093/12728 ~ 7 ~ PCT/US92/113 argon laser, a holmium:YAG laser or other light energy emitting laser, pulsed or continuous wave.
A rectal or trans-urethral ultrasound imaging system, a fluoroscope or other imaging device can be used to ascertain the shape, size and weight of the prostate and to estimate the desired contour of the tissue zone to be irradiated.
Referring to FIG. 7, using an uncooked potato as a model because it exhibits similar light distribution (absorption) characteristics as the human prostate at a wavelength of approximately 1060 nanometers, and applying 40 watts of light energy from a neodymium:YAG laser through the lateral-lasing-fiber-I ` optic device 24 for 60 seconds at the 12, 3, 6 and 9 1 15 o'clock posi~ions, or alternatively, at the 1:30, 9:30, 7:30 and lO:30 o'clock positions, during infusion of sterile water at 50 cc per minute, a consistent, generally spherical damage zone can be obtained in the potato. The diameter of the damage zone measured approximateIy 2.8 centimeters.
Since the human prostate is generally oval in cross section, usually it is preferable to produce an oval zone of tissue ablation and coagulation, thereby reducing the risk of damage to the prostatic capsule and surrounding veins at 12 o'clock and the prostatic ~: capsule and underlying rectum at 6 o'clock.
~n the case of an average-sized prostate of oval cross section and a weight of 25 to 35 grams, to ac~ieve the desired o~al zone o* tissue coagulation, the preferred power level, duration of light energy emission and fluid flow rate are such as to elevate the tissue temperature in the ~esired zone of trea~ment to a valve of about 60C to about 100C. To this end, approximately 40 watts for approximately 30 seconds in the 12 and 6 o'clock positions ~nd approximately 60 :j W~.93/12728 PCT/US92/11368 7 ~

seconds in the 3 and 9 o'clock positions, respectively, are applied. An aggregate of approximately 7,200 joules of energy, with an irrigation fluid flow rate of about 50 cc per minute throughout ~he procedure, is usually applied under such conditions. The total amount of : energy applied during the treatment of the prostate can be in the range of about 4,500 joules to about 10,000 joules.
~1 To illustrate the effect of the above described technique, delivery from a neodymium:YAG laser to an uncooked potato model through a lateral-lasing fiber-optic device similar to that shown in FIG. 1 of 40 watts of light energy for 30 seconds in the 12 and 6 o'clock positions and 60 seconds in the 3 and 9 'clock positions, respectlvely, with an irrigation fluid flow rate of 50 cc:per minute, produced an oval zone of coagulation of approximately 1.9 cm in height and 2.3 cm ~p ~ in width. the approximate contour of the damage zone is : shown in FIG. 8.
~ 20 ~ Ot~her;:methods for reducing the risk of damage `~ to the prostatic~capsule:and adjoining tissues at the 12 and 6 o'clock positions are illustrated in FIGS. 9-12 and describe~d~below~
Referring to FIG. 9, delive-ry of 40 watts of 2~5 light~energy~:from a~neodymium:YAG laser through a lateral-lasi:ng~fiber-optic device .to an uncooked potato ;: for 60 seconds~in each~of four unequal sized quadrants :~ at the 2, 4, 8 and 10 o'clock positions (a total of 9,600 joules),~with fluid~flow at 50 cc per minute, ::produces two:~kidney-shaped zones of damage of an overall size o~ approximately 2.0 to 2.2 cm in height and 2.9 cm in wid~h.
Referring to FIG. 10, delivery of 40 watts of ~ ght energy from a neodymium:YAG laser through a fiber-;~ 3~ optic lateral-lasing device to an uncooked potato for 60 ~:

~ WO93/12728 ~ A ~2 PCT/US92/113~
'~'' ' ;'l .
seconds at each of the 3 and 9 o'clock positions, an !'', .
aggregate of 4,800 joules of energy, with fluid flow at 50 cc per minute, produces two, approximately equal-sized, kidney-shaped zones of coagulation, each of S approximately l.25 cm in height and 0.86 cm in width.
As shown in FIG. ll, delivery from a neodymium:YAG laser through a lateral-lasing fiber-optic device to an uncooked potato of 40 watts of light energy for 90 seconds at the 3 o'clock position and 60 watts of : lO light energy for 60 seconds at the 9 o'clock position, an aggrega~e of 3,600 joules of energy in each position (a total of 7,200 joules), with fluid flow at 50 cc per minute, produces two approximately equal-sized, kidney-shaped zones of damage, each of approximately l.6 to l.7 cm in heigh~ and l.0 cm in width. These zones of damage are smaller than those shown in FIG. 9, due to the relatively lesser amount of energy delivered.
If :a lower level of light energy is deli~ered : for a proportionately longer period o~ time, even if a : total of 7,200 joules of energy are deli~ered to the prostate, a relati~ely smaller zone~ of damage will result, due to hea~ dissipation from the treated tissue during the resulting longer period of irradiation.
As sho~n in FIG. l2, delivery from a . neodymium:YAG laser through the l~teral-lasing fiber-~; optic device: 24 to :an uncooked potato mold of 30 watts : of light energy fox 80 seconds at the 3 and 9 o'clock positions,:an aggregate of 4,800 joules of energy, with : fluid flow at 50 cc per minute, produces two approximately equa1-sized, kidney shaped zones of dama~e, each of approximately l.l. cm in height and 0.8 cm in width.
If the size of the prostate or length of the urethra requixes, for example, in prostates su~stantially larger than 30 grams in weight, the :

~ ~ç

, W,~3/12728 Pcr/uss2/l 1368 , .
~ - 19 -,, cystoscope and the lateral-lasing fiber-optic device can be moved longitudinally approximately 2.25 cent}meters and a second zone can be circumferentially or bilaterally lased in the same manner.
Alternatively, the lateral-lasing fiber-optic device can be moved relatively slowly through the lumen, or back and forth within the lumen, over a course appropriate for the length o~ the prostate or uterus, for a predetermined longer period of time in each of the four aforementioned quadrants. A longer time of irradiation is required, if this procedure is utilized, because the cumulative effect of tissue heating ~o the point of coagulation in a particular direction is diminished by movement of the lateral-lasing fiber-optic device. ~lso, if this technique is utilized, ~reater operator skill is required to keep the lateral~lasing fiber-optic ~evice spaced at a substantially uniform distance from tissue or from contacting tissue and suffering damage therefrom as well.
In the~case of a Iateral-lasing fiber-optic device connected to a Nd:YAG l~ser by an optical fiber with a core diameter of 600 microns, at a distance of 20 mm in air, the diameter of the area of laser energy deli~ered to the tissue ~spo~ size) is about l6.3 mm, due to a wi~der beam divergence from reflecti~e surface 27 of metal tip 25, compared to a spot size of about 7.7 mm in the case of light energy emitted directly by an optical fiber at th~ same distance in air whose core diameter is likewise 600 microns. The potential for a greater area of li~ht exposure and the emission of light energy lateral to the axis of the optical fiber, gives the lateral-lasing fiber-optic device an advantage over cvnven~ional optical fibers in applications such as those described herein.
.

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WO 93tlZ728 . ~PCI`/USg2/1 13 21~71~ r~ -The zone of damage will increase if the rate of ~luid flow is decreased, and the damage zone will decrease if the rate of fluid flow is increased. At lower power levels, the damage zone is more severely affected by an increase or decrease in the rate of fluid flow.
The reflective coating material on the metal tip of the lasing device can be a metal such as gold, 3 silver, copper, platinum or other reflective material.
In one embodimen~, the metal tip is made of a metal alloy, e~g. stainless steel.
In a further embodiment ~FIG. 6), the metal tip can contain an inset reflector member, which can be t~ ~ a mirror, prism, or the like, in which case the amount of light reflected is relatively higher and ~he amount of light absorbed by the tip is relatively lower, resulting in reduced incidental heating of the metal . ~ tip. Alternatively, the inset member can be made of fused silica, sold under the trademark Pyrex, which has :
~ 20 high thermal shock resistance, or diamond or sapphire.
,. ~ ~ A reflective coating can be applied to the surface of such inset, if desired, by vacuum deposition of alternate layers of magnesium fluoxide and cerium oxide films. The thickness and type of the reflective coating depend~ on the wa~elength of the incident light energy a~d the angle~of incidence thereto. Such coatings are known in the;art.
In a laboratory experiment about 40 watts of neodymium:YAG laser energy was delivered to two lateral-lasing fiber-optic devices in air, one with a gold ; reflective coating only on the reflective surface within ~; the ca~ity of the metal tip, and the other with a gold reflective coating over the entire outer surface of the metal tip. A thermocouple placed 1 cm from the side opposite the cavity of each device indicated a maximum .~, :

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o~
W~3/12728 PCT/US~2/l1368 ~ temperature of 26.4C in the case of the metal tip 25 .~' with a reflective coating only on the interior i reflective surface 27, and 2S.6C in the case of the :3 metal tip whose entire outer surface was reflectively coated.
The optical fiber to which the metal tip is mounted may have a core diameter of about 200 to about 1000 microns, preferably about 600 microns. The proximal end of the optical ~iber can incorporate an SMA~type or other optical fiber connector to a laser, which can provide light energy at various wavelengths from 300 nm to about 2,500 nm, from the ultraviolet to infrared, but preferably at a wavelength of 1064 nanometers, the wavelength generated by a neodymium:YAG
laser. With special:fi~er optics, e.g., a zirconium fluoride fi~er, wavelengths as long as 3,100 nm can be : used.
Since the method~described herein does not involve the use of an electric current, saline may be 20: used for irrigating the:treatment zone or region instead of a glycine solu~ion, an amino acid containing solution.~ Alternatively, a so~bitol-mannitol solution or sterile water can~be used for:irrigation purposes.
Howe~er, steriIe water is hypotonic and, in excess, can ; 25 ~ be harm~ul to~the;patient. :~ ~
McPhee,~:~in ~he publications cited above, states that ~he:uncooked potato has: an ex~inction coefficient~for light energy at a wavelenyth of approximatel:y 1060:nanometers, similar to that of the R3327-AT prostatic cancer in:F1 hybrid CQpenhagenJFisher : ~ ~ rats, and tissue:distribution comparable to that of the : prostate in humans. In a series of experiments using uncooked potatoes as models, a central core having a diameter of approximately 0.8 centimeters was removed ~ 35 and,: wi~h continuous fluid flow at a rate of :

~ 22 -approximately 50 cubic centimeters per minute, varying amounts of l~ght energy were applied at various positions for varying periods of time. Staining slices of the potato after lasing with iodine made the lesions produced by the light energy easy to demarcate and measure. The dimensions of the zones of damage produced are approximated in FIGS~ 7 through 12. Reducing the power, even with an inversely proportionate increase in the duration of lasing, produced a smaller zone of damage, as illustrated in FIGS. ll and 12.
While the density of the tissue from one potato to another will vary, the ratios of the sizes of the ~ones of damage illustrate the relative effects of delivery of laser~light energy, as shown in FIGS. 7 lS through l2.
In ~another embodiment, to prevent destruction of the metal tip if the reflective coating thereof is burned away or the reflective surface is disrupted by (a) inadequate~fluid flow for proper temperature control, (b~delivery of too high a level of light energy, tcj~exposure to light energy for too long a period of time or ~d)~adherence of burned tissue if the reflective surface;comes in contact tissue during laser use, the meta~l~tip~may contain a thermocouple, or other ~ 25 temperature sensing device, which is able to detect and ;~ transmit ~he~temperature of metal tip to a logic circuit (not shown~ which~is programmed to ~a) trigger an alarm, ~b) reduce or increase the amount of light energy necessary t:o maintain the desired temperature, and/or (c) shut-down the laser if the temperature of metal tip exceeds or falls below pre-set temperature levels, which may vary from approximately Ç0 to 100C.
Laser transurethral prostatectomy was satisfactorily performed in seven dogs. In each case, urinary continence was preserved. The technique proved :~ .
:

i W ~ 3/12728 PCT/VS92/11368 f~ ~127~
;
~, - 23 -to be a simple and safe procedure, and did not require catheter drainage.
~ Seven adult mongrel dogs weighing between 52 .7' and 72 pounds were given general anesthesia, consisting of thiopental sodium in the amount of 3 to 4 milligrams per kilogram, and atropine in the amount of 1 milligram, followed by halothane sufficient to maintain anesthesia.
Since the dogs' urethra is too small for insertion of a 23 French or larger cystoscope, a midline lower abdominal incision was used to expose the bladder, which was secured in place around a 0-chromic purse-string suture. The cystoscope was advanced into the prostatic urethra and, under direct vision, the lateral-lasing, fiber-optic device of the type shown in FIG. 1 was placed at the level of the verumontanum. Vsin~ a neodymium:YAG laser, varying amounts of power were applied during an appropriate rate of fluid flow for various perivds of time at the 12, 3, 6 and 9 o'clock ;~ ~ positions.
The first dog~was s~crificed immediately and the prostate~removed for histologic examination. The cystotomy in tpe remaining six dogs was closed using a 3-0 chromic c tgut suture, the abdominal incision was closed with~interrupted 2-0 vicryl sutures, and the skin was~closed~with~fine~wire in an interrupted fashion. No urinary catheter or drains were left indwelling at the en~ of the~procedure~. Each dog received 500 milligrams of chloramphenicol, an antibiotict three times a day beginnin~ on the~day of surgery and for seven consecutive day~s thereafter. The dogs were allowed to drink~ and resume acti~ity immediately after surgery.
Over a period of weeks, the remaining tissue in the coagulation (thermal necrosis) zone was absorbed by the body or sloughed-off in a mucous-like effusion, with ,~
,~;;

i:~

WO93/12728 PCT/US92~1136 ................ .....2~ ,7~s~7' - ~4 -little or no particular matter appearing in the urine or mucous-like effusate.
The remaining dogs were sacrificed 8 weeks after surgery. At that time, the bladder,.prostate and proximal urethra were remo~ed, fixed in 10% neutral buffered formaldehyde solution ~Formalin), and later '~ sectioned and embedded in paraffin for histologic assessment. No animal was observed to have suffered ~`; bleeding, and only one required short-term urethral catheterization. Continence was maintained in all animals. Examination of the prostate immediately after lasing (Dog 1) acutely revealed a well-demaroated sphere of thermal necrosis having a diameter of approximately 2.6 cen~imeters. In the other six animals, the transurethral defects were proportional to the amount of light energy used. In each instance, after about eight ~ri wee~s, transitional epithelium had relined the prostatic cavity, the adjacent parenchyma showed glandular atrophy and fibrosis:, and the capsule of the prostate was intact. ~ :
In 20:human patients treated with laser ~; :~ transurethral prostatic resection, a 23 French or larger cystoscope was~used, and the procedure was successfully : carried out under~endoscopic or other ~iewing in a G
¢ 25 manner consistent:with the method described above.
.- ~ A catheter ~as left in place in the ure~hra for a day or two to maintain urine flow, as some swelling of the~prostate occurred from the thermal , ~ ~ coagulation, which resolved without complication. In . ~ 30 all cases~ urine;flow was slightly increased after :~ ~ removal of the catheter. The coagulated tissue was ~ slowly absorbed ~y ~he body or sloughed-o~f in a mucous-i~ like effusion with minimal particulate matter during a i : period of up to three to four weeks.
,.?~, .'~

~W ~ 3/12728 PCT/US92/11368 2 3 ~ t~

Urine flow increased daily during a period of two to three weeks after the procedure, from an average pre-procedure urine flow rate of about 9 cc per second to an average 14.75 cc per second approximately one month following the procedure.
.There was little or no post-operative bleeding or pain, hospitalization was 1 to 2 days, no blood transfusions were required, the patients returned to normal activities after one to three days of recuperation at home, continence was preserved and erectile potency was unaffected.
Subsequently additional five human patients were treated with laser transurethral resection in the mannex described:above, except the input energy level, 15 : time of lasing and directions were 40 watts for 30 econds at the 12 and 6 o'clock positions and 60 seconds at the 3 and 9 o'clock positions, respectively. The results were substantially the same as described above.
Some small popping sounds were occasionally heard and ruptures of the inner, treated surface of the : urethra ~were:occasionally observed with the input of 60 ~ wa~ts of Nd:YAG~laser energy, possibly due to the :~: creation of steam::in: pockets below the surface during lasing.: Little~or no~bleeding and no adverse effects fr~m:~these:ruptures was seen, however. At lower light ~; ~ . energy input levels,~such as 40~ watts of Nd:YAG laser :energy,~ such popping ~sounds or: ruptures were infrequently noted.
To treat excessive bleeding of the endometrial `: 30 ~ lin~ng of the~ uterus, the lateral-lasing fi~er-optic device may be inserted into the uterus through an :~ endoscopic device and properly positioned in the center of and approximately 1 cm from the fundus of the uterus.
Light energy from a neodymium:YAG laser may be delivered through the lateral-lasing fiber-optic device, with `~' "~1 :
W~93/~2728 PCT/US92/l1368 ~ Q 2 ., - 2~ -sufficient flow of a biocompatible fluid throughout the -~ procedure to distend the uterus to an extent desirable to obtain ~isualization and keep tissue from contacting metal tip, at power levels of from 20 to 60 watts for 20 to 60 seconds, dependins on the cross sectional dimensions of the distended uterus, which may be estimated by ultrasound imaging, at each of the 12, 3, 6 and 9 o'clock positions or 2,4, B and 10 o'clock positions, to obtain the desired depth of coagulation, appxoximately ~ to 7 mm.
Depending on the estimated length of the uterus, the lateral-lasing fiber-optic device may be withdrawn approximately 2.25 cm and the lasing procedure with fluid flow, both as described a~ove, may be repeated. If appropriate, the above describe~ lasing procedure with fluid flow may again be repeated in a third location.
~ As the cross-sectional size of the uterus z ~ decreases, the amount of energy and/or the amount of time may be reduced, and the rate of fluid flow may be adj~sted to~produce the desired distention of the uterus .
for proper visualization, while maintaining a lumen sufficient t~;prevent tissue ~from contacting the metal tip of the lateral lasing fiber optic device.
2S To minimize excessive fluid infusion into a body cavity or organ, the lateral-lasing fiber-optic de~ice can be~;~c~ontained within a balloon in a manner similar to that shown in commonly-owned U.S. Patent No.
4,470,407 to Hussein. The device-enveloping balloon can be made of a material which is transparent to the wa~elength of light energy used, such as silicone film or polyurethane film of 0.05 mm to 1 mm in thickness, preferably about 0.2 mm to 0.5 mm in thickness, in the case of a Nd:YAG laser of 10~ nm. The balloon can be .? 35 in a shape that is complementary to the interior contour ~", ~:
:~
~$
,.-~ W ~ 3/12728 PCT/US92/l1368 . 2 !$~ fl ~? ~
''-'' of the organ, cavity of lumen being trea~ed. For example, the balloon can be in a tubular, triangular shape for use in the uterus. Fluid is circulated in the balloon, which is distended to the interior surface of the body cavity, organ or lumen. Continuous fluid flow during lasing can optionally be utili7-ed to maintain a desired temperature in the lasing region.
From the foregoing, it can be seen t~at a simple, safe, effective and rapid method of unwanted tissue removal from a body lumen, cavity or organ, usin~
a lateral-lasing fiber-optic device, for example, to vaporize or coagulate prostatic tissue in the prostate or endometrial tissue in the uterus endoscopically, has been described.
Additionally, in the event a tumor or growth of tissue, an ulcer or one or more blood vessels in need of cauterization lie in a particular direction in a body lumen, cavity or organ, an endoscope or other viewing system can be used to properly position the lateral-~ lasing fiber-optic device to direct an appropriate amount of light energy from the~laser for an appropriate period of time in the direction of the tumor or growth, ~lcer or bleeding vessels to obtain the desixed zone of ablation or coagula~ion. For example, the method 2~ described above~may be used ts ablate endometrial tissue in the abdominal cavity to treat ehdometriosis, to aporiæe or coagulate cancerous tissue in the uterus, prostate or other body lumen, cavity or organ, or to cauterize an ulcer or bleeding bl~od vessel in the stomach or elsewhere.
Since tum~rs, due to generally inadequate ; circulation, are less able to dissipate heat, the ' lateral-lasing fiber-optic device may also be used to simply raise the temperature of a tumor by 5 to 6 centigrade for an appropriate period of time, generally ~ WO93/12728 PCT/US92/113~
~ ~ 2 1 ~ ~

5 to 40 minutes, and selectively cause the death of the tumor cells/ without creating sufficient heat to cause thermal necrosis of adjoining normal tissues.
Since the area of impinging light energy (spot size) emitted from lateral-lasing fiber-optic device is larger than that emitted from a conventional optical fiber, lateral-lasing fiber-optic device can be used to deliver light energy of an appropriate wave-len~th to activate a photo-active drug, such as a hematoporphyrin derivative, in which case an argon laser might be used, a psoralen, in which case an excimer or other ultraviolet light generating laser might be used, or the like, which photo-active drug has accumulated in the unwanted tissue as a result of the earlier .~ 15 administration of same to the patient.
In certain of the above instances, for example, in cauterizing a bleçding ulcer in the stomach, the presence of existing stomach fluids may reduce or negate the need for fluid flow. In other instances, for example, in removal of endometrial tissue in the abdominal cavity where little fluid exists, fluid flow ~:~ or a spray of biocompatible liquid or a gas, such as : carbQn dioxide,~may be used to control the temperature of metal tip and the sarget tissue.
~;: 25 Thè~apparatus of this invention may be :.
employed with~ conventional optieal fibers, a suitable con~entional laser, a Iogic system and coupling system ~ therefor, the details of which, although not fully : illustrated vr described, will be apparent to those : ~ 30 having skill in the art and an understanding of the necessary functions of such devices. The detailed descriptions of such devices are not necessary to an ., understanding of the invention and are not herein presented because such devices form no part of the . present invention.

.~ W~93/12728 PCT/US92/11368 - ~S~ .a2 While this invention may be embodied in many different forms, this specification and the accompanying drawings disclose only some specified forms as examples of the invention. Accordingly it is intended that the foregoing disclosure and showing made in the drawings shall be considered only as an illustration of the principles of the present invention and not as a limitation.
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Claims

WE CLAIM:

1. A method for the removal of unwanted tissue comprising the steps of:
positioning an elongated lateral-lasing fiber optic device adjacent a selected region of the tissue to be removed;
delivering a biocompatible fluid at a predetermined rate of flow contiguous with the .
positioned lateral-lasing fiber optic device; and energizing the positioned lateral-lasing fiber optic device at a predetermined power level to emit laser energy in a direction substantially transversely to the longitudinal axis of the later-lasing fiber optic device and so as to irradiate the selected region of the tissue to be removed for a predetermined time period to produce a zone of coagulation in the irradiated tissue.

2. The method according to claim 1, in which the flow rate of said biocompatible fluid is in the range of 20 to 200 cubic centimeters per minute.

3. The method according to claim 1, in which the light energy is generated by a neodymium:YAG laser.

4. The method according to claim 1, in which the light energy is generated by a holmium laser.

5. The method according to claim 1, in which the power level and duration of light energy emission from a neodymium:YAG laser and the fluid flow rate are, in the case of laser transurethral resection of the prostate, approximately 40 watts for approximately 30 seconds in the 12 and 6 o'clock positions and approximately 60 seconds in the 3 and 9 o'clock positions, respectively, with fluid infusion at the treatment site at a rate of approximately 50 cc per minute.

6. The method according to claim 1, in which the power level and duration of light energy emission from a neodymium:YAG laser and the fluid flow rate are, in the case of laser transurethral resection of the prostate, approximately 40 watts for approximately 60 seconds at the 2, 4, 8 and 10 o'clock or the 3 and 9 o'clock positions, respectively, with fluid flow at approximately 50 cc per minute.

7. The method according to claim 1, in which a viewing system for positioning is an endoscope.

8. The method according to claim 1, in which more than one circumferential or bi-lateral zone of lasing is performed on tissue in a body lumen, cavity or organ.

9. The method according to claim 8, in which the body lumen is the prostatic urethra and the body organ is the prostate.

10. The method according to claim 1, in which the body lumen is the uterus.

11. The method according to claim 1, in which the procedure is a laser transurethral prostatic resection.

12. The method according to claim 1, in which the procedure is endometrial ablation of the uterus.

13. A method for removing unwanted tissue in a body lumen, cavity or organ, which comprises the steps of:
(a) using a viewing system to position in a body lumen, cavity or organ opposite said unwanted tissue a lateral-lasing fiber-optic device having at the distal end thereof a reflectively-coated metal tip mounted to an optical fiber, which tip is capable of directing by reflection the light energy from a laser laterally from the axis of the optical fiber; and (b) delivering, while infusing a biocompatible fluid at a predetermined flow rate, or in the presence of sufficient fluid, a predetermined amount of light energy from a laser to said unwanted tissue for a predetermined period of time to obtain the desired zone of coagulation.

14. The method according to claim 13, in which the light energy is generated by a neodymium:YAG
laser.

15. The method according to claim 13, in which the light energy is generated by a holmium laser.

16. The method according to claim 13, in which the body lumen is the prostatic urethra, the body cavity is the abdominal cavity and the body organ is the prostate.

17. The method in accordance with claim 1, wherein said unwanted tissue is infused with a photoactive agent prior to irradiation.

18. The method in accordance with claim 1 wherein said light energy is delivered from a pulsed laser and the temperature of the tip is monitored.

19. The method in accordance with claim 13 wherein the reflectively-coated metal tip is contained within a balloon transparent to the wavelength of said light energy.

20. A device for applying a laser energy beam to a selected body site comprising:
an elongated, laser energy transmitting conduit having a proximal end and a distal end;
a laser energy source optically coupled to the proximal end region of the conduit for transmitting laser energy along the conduit;
a hollow, apertured element mounted on the distal end of said conduit and provided with an internal laser energy reflective surface so that a major portion of the laser energy transmitted by the conduit to the bulbous element impinges thereon and exits from the element laterally as a laser energy beam; said element defining a cavity within which the distal end of the conduit is received and further defining an aperture communicating with said cavity and positioned to one side of the laser energy path entering said cavity but in registry with the laterally exiting laser energy beam; and an operculum over said cavity; said operculum being permeable to the laser energy beam but preventing body tissue entry into said cavity.

21. The device according to claim 20 wherein the operculum is a bar that extends longitudinally across said cavity.

22. The device according to claim 20 wherein the operculum is a plurality of bars across said cavity

23. The device according to claim 20 wherein the operculum is a laser energy transparent baffle that extends partially across said cavity.

24. The device according to claim 20 wherein the operculum is a laser energy transparent lid over said cavity.

25. The device according to claim 20 wherein the operculum is a laser energy transparent lid over said cavity and wherein the lid and said hollow apertured element together define a sealed sapce therebetween.

26. The device according to claim 20 wherein the laser energy beam exits the hollow element through said operculum and in a direction substantially transverse to the major axis of the elongated, laser energy transmitting conduit at the distal end region of the conduit.

27. The device according to claim 20 wherein an energy reflective surface layer for receiving and reflecting the laser energy transmitted by the conduit is provided within said cavity and in the path of the laser energy beam emitted from the conduit.

28. The device according to claim 20 wherein the energy reflective mirror surface is defined by a layer of gold.

29. The device according to claim 20 wherein a reflective coating is provided on the external surface of the hollow element.

30. The device according to claim 20 wherein the energy reflective surface is provided by an inset mounted in the hollow element and situated in the path of a laser beam exiting from said conduit.