while the specification concludes with claims defining the features of the invention that are regarded as novel , it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures , in which like reference numerals are carried forward . before the present invention is disclosed and described , it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting . it must be noted that , as used in the specification and the appended claims , the singular forms “ a ,” “ an ,” and “ the ” include plural references unless the context clearly dictates otherwise . referring now to the figures of the drawings in detail and first , particularly to fig2 thereof , there is shown a first embodiment of a pressure - limiting balloon catheter 100 that does not inflate past the tearing limit of a lumen in which the catheter 100 is placed , for example , in the urethra . to prevent occurrences of urethra tearing due to premature - improper inflation of the balloon and / or due to premature removal of an inflated balloon , the invention of the instant application provides the balloon 110 with a balloon safety valve 112 . as set forth above , in a balloon 3 of a conventional catheter ( see reference numerals 1 to 5 in fig1 ), the balloon 3 is fixed to the outer surface of the fluid drainage line 120 ( not shown in fig1 ) and is not intended to be removed therefrom or to burst thereon unless an extraordinary amount of inflation occurs . such a tearing event is not supposed to occur under any circumstances during use with a patient . if such an event happens , the material of the balloon 3 will open at a random location , based upon the microscopic fractures or weaknesses in the material itself , and risk of serious damage to the patient is associated with the bursting , as well as a risk of balloon fragmentation , which could leave pieces of the balloon 3 inside the patient after removal of the catheter . in contrast to such conventional devices , the balloon 110 of the present invention is created specifically to tear when a predefined pressure exists in or is exerted on the balloon 110 . the controlled tear will occur because the balloon safety valve 112 is present . conventional balloons have constant balloon wall thicknesses . in contrast thereto , the balloon safety valve 112 in the first embodiment is a defined reduction in balloon wall thickness . this reduction creates a breaking point or selected breaking points at which the balloon 110 is intended specifically to break when a predefined force exists in or is imparted on the balloon 110 . because the balloon 110 is made of a material having a known tearing constant — dependent upon the thickness thereof ( which is determined experimentally for different thicknesses of a given material prior to use in a patient ), the balloon safety valve 112 of the present invention for urethra applications is matched to break when the pressure inside or exerted on the balloon 110 approaches the maximum urethra pressure . in the embodiment shown in fig2 , a decreased thickness is formed as a first semi - circumferential groove 114 near a proximal end of the balloon 110 and / or as a second semi - circumferential groove 116 near a distal end of the balloon 110 . the grooves 114 , 116 can have any cross - sectional shape , including , trapezoidal , triangular , square , or rectangle , for example . because rubber , plastic , and silicone materials tear well with thinner cuts , a relatively triangular shape or one with a narrow bottom is preferred . to make sure that the entire balloon 110 of the illustrated embodiment does not completely tear away from the fluid drainage line 120 , both grooves 114 , 116 do not extend around the entire circumference of the balloon 110 . as shown to the left of the proximal groove 116 in fig2 , the groove 116 is not present on at least an arc portion 118 of the circumference of the balloon 110 . the arc portion is defined to be sufficiently large so that , when the catheter 100 is removed from the patient , the balloon 110 cannot tear away entirely from the catheter 100 ( and create the disadvantageous fragmentation situation as set forth above ). the illustrated balloon safety valve 112 is , therefore , fashioned to keep the balloon 110 in one piece after breaking and firmly connected to the catheter 100 to insure that no piece of the balloon 110 will be left inside the patient after actuation of the balloon safety valve 112 . it is noted that the balloon 110 is inflated through an inflation lumen 130 having a proximal opening , typically formed by a female end of a luer connector . the female end is connected to a non - illustrated inflation device , for example , a distal end of a syringe for inflation of the balloon 110 . in this first embodiment , the balloon can be of rubber , silicone , or plastic , for example . once the balloon breaks , the catheter is useless and must be discarded . because the balloon 110 in this embodiment will break inside the patient , it should be inflated with a bio - safe fluid to prevent an unwanted air or gas from entering the patient . in certain circumstances where balloon catheters are used , air or gas will not injure the patient if let out into the patient &# 39 ; s body cavity . in such circumstances , the inflating fluid can be air under pressure , for example . maximum urethra pressure can also be tailored to the individual patient . based upon a urethral pressure - measuring device , the patient &# 39 ; s maximum urethra pressure can be measured before the catheter 100 is placed therein . a set of catheters 100 having different safety valve breaking constants can be available to the physician and , after estimating or calculating or knowing the patient &# 39 ; s maximum urethra pressure , the physician can select the catheter 100 having a safety valve breaking constant slightly or substantially smaller than the patient &# 39 ; s maximum urethra pressure . accordingly , if the pressure in the balloon 110 approaches the patient &# 39 ; s maximum urethra pressure for any reason , whether it is due to over - inflation , improper placement , and / or premature removal , the balloon 110 is guaranteed to break prior to the patient &# 39 ; s lumen , in particular , the patient &# 39 ; s urethra , prior to causing iatrogenic injury . a second embodiment of the one - use breaking safety valve of a pressure - limiting balloon catheter 200 is shown in fig3 . the catheter 200 has a fluid drainage line 220 , a balloon inflation lumen 230 , and a secondary lumen 240 . the fluid drainage line 220 is connected fluidically to the body cavity ( i . e ., the bladder 30 ) for draining fluid from the body cavity . the secondary lumen 240 can be used for any purpose , for example , for housing the radiation line that will supply energy to the radiation coil 2 . it can also be used for injecting fluid into any distal part of the catheter 200 or even the body cavity itself . the balloon inflation lumen 230 begins at a proximal end with an inflating connector 260 that , in a preferred embodiment , is a female luer connector ( of course , it can be a male luer connector too ). the balloon inflation lumen 230 continues through the body of the catheter 200 all the way to the balloon and is fluidically connected to the interior of the balloon . the balloon safety valve is also fluidically connected to the balloon inflation lumen 230 . in the second embodiment of the safety valve 212 , the valve 212 is formed integrally with the balloon inflation lumen 230 and is set to open into the environment ( instead of into the patient ) if the maximum urethra pressure is exceeded in the balloon or the balloon inflation lumen . because this safety valve 212 is located near or at the balloon inflation port 220 in this configuration , fluid used to inflate the balloon will not enter the patient when the valve 212 opens . the safety valve 212 in the second embodiment can merely be a narrowing of the distance between the balloon inflation lumen 230 and the outer surface 250 of the catheter 220 . in fig3 , the valve 212 has a rectangular cross - section and extends away from the balloon inflation lumen 230 . as shown in fig4 , 5 , and 6 , respectively , the cross - section can be triangular ( peaked or pyramidical in three - dimensions ), curved ( circular or cylindrical in three - dimensions ), or trapezoidal ( frusto - conical or bar - shaped in three - dimensions ). the cross - sections are shown in fig3 to 7 with the narrowing emanating from the balloon inflation lumen 230 outward . as an alternative , the narrowing can begin on the outer surface of the catheter and extend inwards towards the balloon inflation lumen 230 . a further alternative can have the narrowing extend from both the lumen 230 and the outer surface of the catheter . the cross - sections illustrated are merely exemplary . what is important is that the thickness t between the bottom 213 of the valve 212 and the outer surface 250 of the catheter 220 in comparison to the thickness t of the catheter body over the remainder of the balloon inflation lumen 230 . an enlarged view of this thickness comparison is illustrated in fig7 . as long as the thickness t is smaller than the thickness t ( t & lt ; t ), and as long as the force fb required to break the balloon is greater than the force fsv required to break the portion 213 of the safety valve 212 ( fb & gt ; fsv ), then the portion 213 of the safety valve 212 is virtually guaranteed to break every time pressure exerting a force f in the balloon inflation lumen 230 is greater than the force fsv required to break the safety valve ( fsv & gt ; f ). based upon this analysis , the force fsv required to break the safety valve can be tuned to whatever a patient needs or a physician desires and different sized valves can be available for any procedure and provided in the form of a kit . whether a standard maximum urethra pressure is used or a patient - specific maximum urethra pressure is measured and used , experiments can be conducted prior to use on a patient on various catheter thicknesses t to determine the pressure needed to break the portion 213 of the safety valve 212 . for example , ten different maximum urethra pressures can be known as desirable setpoints and the thicknesses t can be varied such that pressure required to break the ten thicknesses correspond to the ten setpoint pressures . if , then , ten catheters are placed in such a kit , each having one of the ten thicknesses , then the physician has a range of 10 maximum urethra pressure values to use with the patient . the safety valve 212 of the second embodiment need not be confined to the body of the catheter 200 . instead , the inflating connector 260 can be equipped with the safety valve 212 . alternatively , a modular attachment 270 containing the safety valve 212 can be attached to the inflating connector 260 . such a modular valve attachment 270 is removable and replaceable ( such as through a convention luer or even a screw - threaded connection ). accordingly , as long as the catheter 200 can still be used after the valve 212 actuates ( breaks ), the used attachment 270 can be replaced with a new attachment 270 . the converse is also true for reuse of the attachment 270 if the catheter 200 breaks and the valve of the attachment 270 remains unbroken . one embodiment of the attachment is illustrated in fig9 . specifically , an upstream end of the connector 260 is attached removably to a downstream end 272 of the modular valve attachment 270 and the upstream end 274 of the attachment 270 is attached to the female connection of the balloon inflation device 280 illustrated only diagrammatically in fig9 . a common exemplary inflation device 280 is a syringe . in such a configuration , the safety valve 212 , 312 of the present invention can be entirely separate from the catheter 200 , 300 and , therefore , form a retrofitting device for attachment to the luer connector present on conventional catheters . as an alternative to the one - use breaking safety valve of the second embodiment , a multi - use pressure valve can be used . this third embodiment of the pressure - limiting balloon catheter 300 is illustrated in fig8 . the catheter 300 can be the same as the catheter 200 in fig3 except for the portion illustrated in fig8 . instead of having a narrowing thickness t of the lumen wall , the valve portion 313 extends entirely to the environment . however , a one - way valve 314 ( shown only diagrammatically in fig8 ) is attached to the open end of the valve portion 313 and is secured to the outer surface 250 of the catheter 300 to close off the open end of the valve portion 313 . the one - way valve 314 can be secured directly to the outer surface 250 ( e . g ., with an adhesive ) or a connector 315 ( e . g ., a threaded cap ) can secure the one - way valve 314 to the open end of the valve portion 313 . regardless of the configuration , the one - way valve 314 includes a device that does not permit fluid from exiting the lumen 230 until a given resistance r is overcome . this given resistance r can be selectable by the physician depending upon the one - way valve that is chosen for use if a set of one - way valves having different resistances r are available for use by the physician . just like the second embodiment , the resistance r can be set to correspond to desired maximum urethra pressure values . therefore , when used , the fluid exits the one - way valve 314 into the environment well before the patient &# 39 ; s maximum urethra pressure is exceeded by the balloon . the one - way valve 314 can be a mechanical one - way valve . additionally , the one - way valve 314 can be a material having a tear strength corresponding to the desired set of resistances r . the material can be a fluid - tight fabric , a rubber , a plastic , or silicone different from the material making up the catheter . the material can even be a rubber , plastic , or silicone the same as the material making up the catheter but having a reduced thickness t than the thickness t of the catheter . because the safety valve 212 , 312 is located at the proximal end of the catheter 200 , 300 , the distal end of the catheter 200 , 300 can take the form of a distal end of a conventional balloon catheter 2 , 3 , 4 , 5 . alternatively , the distal end shown in fig2 can also be used for redundant over - pressure protection . the catheter 200 , 300 according to the invention can be used in vascular applications . it is known that every vessel has a tearing pressure . balloons are used in coronary arteries , for example . if a coronary artery balloon were to burst , there would be less damage if the burst was controlled according to the invention . the same is true for a renal or iliac blood vessel . in such situations , the breakaway catheter improves upon existing catheters by making them safer . from the urinary standpoint , the breakaway balloon will not only prevent injury , but will also be a signal to the technician that he / she needs to obtain the assistance of a physician or urologist with respect to inserting the catheter . referring now to fig1 thereof , there is shown a first embodiment of an illuminating balloon catheter 100 having a distal balloon 110 , a catheter body 102 , and a drainage assembly 150 . the catheter body 102 defines a fluid drainage lumen 120 , a balloon inflating lumen 130 , and an illumination device lumen 140 . the distal end of the drainage assembly 150 is explained below with regard to fig1 and includes a shaft on which or around which the balloon 110 is connected . the drainage assembly 150 has at least one distal drainage port 152 at the proximal end of the catheter 100 for draining fluid from a body cavity ( i . e ., urine from a bladder ). the drainage assembly 150 can also be integral with or connected to the catheter tip 154 . the interior of the balloon 110 is fluidically connected to the balloon inflating lumen 130 . the balloon 110 is inflated through a connector 160 disposed at a proximal opening 132 of the inflation lumen 130 . see fig1 . typically , a female end of a luer connector forms the connector 160 and is shaped to connect to a non - illustrated inflation device , for example , a distal end of a syringe for inflation of the balloon 110 . fig1 illustrates an exemplary embodiment of the proximal end of the catheter 100 of the present invention . the proximal end includes the proximal portions of the fluid drainage lumen 120 , the balloon inflation lumen 130 , and the illumination device lumen 140 . the fluid drainage lumen 120 is fluidically connected at a proximal end thereof to a drainage device having a drainage funnel 122 defining a proximal , substantially circular opening 124 within which is received a fluid connection device 170 , indicated in fig1 diagrammatically with dashed lines . the balloon inflation lumen 130 begins at a proximal end with the inflating connector 160 , continues through the body 102 of the catheter 100 all the way distal to the balloon 110 and is fluidically connected to the interior 112 of the balloon 110 as set forth above . the illumination device lumen 140 is formed to house a directional illumination source 201 , shown ( in a first embodiment in fig1 ) as a fiber optic strand having a distal end 202 terminating flush with a transparent portion of the balloon 110 . this strand supplies light into the balloon 110 . thus , all of the light emanating from the distal end 202 of the strand is coupled into the cavity 112 of the balloon 110 . a conventional fiber optic light source can be coupled to the fiber optic strand and , therefore , is not described in further detail nor is it illustrated more than diagrammatically with box 204 in fig1 . without anything further , if the balloon 110 were entirely transparent , the light entering the balloon 110 would enter the cavity 112 and pass entirely through the balloon 110 out the distal side thereof . the present invention , however , provides a reflective surface 210 on the balloon 110 . the reflective surface 210 is shown on the interior of the balloon 110 , however , it can be on the exterior of the balloon 110 as well . the reflective surface 210 can be a coating thereon or it can be a natural property of the material making up the balloon 110 . in fig1 , the reflective surface 210 is shown covering approximately half of the interior surface of the balloon 110 , i . e ., it is substantially hemispherical . thus , the light will emanate from the balloon 110 over the proximal hemispherical half and only illuminate structure located on the proximal side of the balloon 110 ( below the balloon in fig1 ). this configuration , however , is merely exemplary because the reflective surface 210 can be fashioned to traverse any extent on the balloon 110 . also , it need not be symmetrical . in the hemispherical shape of fig1 , the reflective surface forms a concave minor and , therefore , focuses light in the proximal direction . alternatively , the reflective surface can be formed asymmetrically to focus and / or direct light at any angle cc with respect to the longitudinal extent of the catheter body 102 . as shown , for example , in fig1 , the reflective surface 210 is disposed on substantially all of the right half of the balloon 110 and is disposed on the distal half of the left side of the balloon 110 and on a portion adjacent the exit of the balloon inflating lumen 130 . in this configuration , the light coupled into the balloon 110 from the distal end 202 is reflected and emanates from the balloon 110 opposite the illuminating source 200 over an arc - shaped area β . thus , if the physician is located on the left side of the catheter 100 with respect to fig1 , and is looking at the catheter 100 in a direction along arrow a , all of the light will be emerging on the side facing the physician and in a relatively proximal direction . such illumination is very beneficial when locating the urethrovesical junction in a laparoscopic prostatectomy . a second embodiment of the illuminating balloon catheter is shown in fig1 . therein , the illuminating device 200 ( e . g ., a fiber optic strand ) is shielded from emitting illumination up until a point at which it emerges into the cavity 112 of the balloon 110 . this unshielded portion 206 allows the light to enter the balloon 110 without be attenuated by the material of the balloon 110 , which occurs to a small extent in the first embodiment . one drawback to this second embodiment is that two holes need to be created in the balloon 100 because the illumination source 200 is in a lumen entirely separate from the balloon inflation lumen 130 . if , however , the balloon inflation lumen 130 is sufficiently large to fit therein the illumination source 200 ( in a fluid - tight fit at the proximal end of the lumen 130 ) and still allow inflation of the balloon 110 without substantial back pressure or closing off of the lumen 130 , then the balloon 110 can be formed with only one hole . such an alternative configuration is shown in fig1 . in this configuration , the secondary lumen 140 becomes available for another useful purpose . fig1 illustrates a fourth alternative embodiment of the illuminating balloon catheter 100 . specifically , the illuminating device 200 ( e . g ., fiber optic ) is led through the fluid drainage lumen 120 and is fastened to the inside surface thereof except for a distal - most portion near the point at which the drainage assembly 150 is secured . the drainage assembly 150 is formed with an intermediate opening 156 that can be fluid - tightly sealed by securing thereto the unshielded portion 206 of the fiber optic device 200 , for example . this embodiment is particularly suited for an led as the illumination source because the intermediate opening 156 can be formed with exact tolerances so that the led can be secured therein easily in a fluid - tight manner with conventional glues . fig1 illustrates a fifth alternative embodiment of the illuminating balloon catheter 100 . specifically , the illuminating device 200 is tubular and is led through the fluid drainage lumen 120 in a longitudinally movable manner . the illuminating device 200 has a distal - most portion at which is disposed an illuminator 206 a . the illuminator 206 a can be formed from an unshielded portion of a fiber optic or can be an led having an illumination direction disposed along a radial line orthogonal to the longitudinal extent of the illuminating device 200 . because the illuminating device 200 can be rotated 360 degrees inside the fluid drainage lumen 120 , a portion of the drainage assembly 150 inside the balloon is transparent . thus , as the illuminator 206 a is rotated within the fluid drainage lumen 120 , the light beam also rotated within the balloon . in this embodiment , therefore , the catheter need not be rotated inside the patient &# 39 ; s urethra . to make sure that a majority of the illumination is directed proximally , the balloon 110 is , in this fifth embodiment , provided with the hemispherical reflector 210 similar to that shown fig1 ( but not shown in fig1 ). it is noted that the hollow structure of the illuminating device 200 allows for virtually unhindered passage of the fluid that is to be drained through the fluid drainage lumen 120 . laparoscopic prostatectomy can be assisted with all of the configurations shown in fig1 to 17 . with the invention of the instant application , the balloon of the catheter is inflated in the bladder and the surgeon or assistant directs the light to help locate the urethrovesical junction . inflation of the balloon such that the proximal portion thereof presses against the proximal wall of the bladder near the urethrovesical junction to compress the tissue at the urethrovesical junction . such compression allows the urethrovesical junction to be very apparent when viewed through a laparoscope . the directed illumination from the illumination device 200 , in combination with the compression of the urethrovesical junction , allows the metes and bounds of the urethrovesical junction to be clearly identified . accordingly , a laparoscopic prostatectomy can have greater chances for success . a fiber optic is used herein as an illustrative example for the illumination source . it should not , however , be deemed as limiting the scope of potential illumination sources . for example , as set forth above , conventional light - emitting diodes ( leds ) can be used . also , printed organic light - emitting diodes ( oleds ) can be used both as the illumination source and as the reflective coating . specifically , if the feature shown as a reflective coating 210 in fig4 and 5 is substituted with a printed oled , then the oled can become an illumination source that does not need reflection to direct illumination from the balloon 110 of the present invention . other similar forms of illumination devices can be substituted or used . the breakaway catheter is not only a separate device from the illuminating catheter and vice - versa . therefore , it is envisioned that the two catheters described individually herein can be combined in any manner into a single catheter with any of the features of both .
to perform a prostatectomy , a directionally illuminating balloon catheter enters a bladder . the catheter has a multi - lumen shaft . the balloon defines an interior fluidically connected to a balloon inflation lumen and is inflated therethrough . the balloon comprises a light source , a light - radiating surface adjacent the shaft - balloon junction , and a substantially opaque surface disposed at a portion of the balloon other than the light - radiating surface such that the integrated light source illuminates a proximal half of the environment outside the balloon . the balloon is inflated while in the bladder . light from the light source is directed out through the light - radiating surface to illuminate at least a portion of a procedure area at the bladder - prostate junction . with the light illuminating the portion of the procedure area , at least a portion of a prostatectomy is performed at the portion of the procedure area .