Abstract:
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.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is:
       a divisional application of U.S. patent application Ser. No. 11/339,258, filed Jan. 25, 2006, and now U.S. Pat. No. 8,883,503 (which application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Nos. 60/647,204 and 60/647,205, filed Jan. 26, 2005); and   a divisional application of U.S. patent application Ser. No. 12/972,619, filed Dec. 20, 2010,
 
the prior applications are hereby incorporated herein by reference in their entireties.
       
 
     
    
     BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    The present invention relates to a catheter, especially a flexible illuminating balloon catheter and a method for using the catheter. 
         [0006]    2. Description of Related Prior Art 
         [0007]    A number of conventional balloon catheters exist in the prior art. Some catheters are used to drain the bladder of a patient during surgical procedure or to treat bladder and/or urethra or prostate conditions, for example. 
         [0008]    For example, U.S. Pat. No. 4,248,214 to Hannah et al. (hereinafter “Hannah”) describes an illuminated urethral catheter for draining the urinary bladder while providing circumferential cold illumination of the adjacent urinary tract. Such illumination enables the surgeon to accurately locate the bladder, junction, and urethra without distorting the same so that, for instance, support sutures may be accurately placed adjacent the urethrovesical junction without injury to the urinary tract. The Hannah catheter emanates light outwardly at its distal end through a fiber optic member in all directions ( 360  degrees) around its circumference. Thus, the Hannah catheter eliminates the need to orient the fiber optic member angularly within the catheter to provide the desired cold illumination of the urinary tract. 
         [0009]    The Hannah illuminated catheter requires the light-emitting surface to extend around the entire circumference of the distal end of the fiber optic so that the need to orient the fiber optic is eliminated. This catheter also has a longitudinally movable fiber optic to move the light-transmitting surface along the catheter tube to a desired location. It is noted that Hannah gives an unclear message regarding the intensity of the light emitted from the proximal-most portion  86  as compared to the ultimate distal tip  82 . On col. 6, lines 30 to 32, Hannah indicates that the “intensity of the emitted light increases from portion end  86  to tip  82 ,” i.e., is greater at the proximal end of the emitting area. But at col. 7, lines 50 to 54, Hannah provides that the “intensity of the light emitted from the fiber optic is greatest at the proximal end of abraded portion  84  nearest the light source so that the required high intensity light is provided to illuminate the urethra and urethral-bladder junction.” 
         [0010]    Hannah teaches that conventional location of the urethrovesical junction by balloon inflation is to be avoided because they “are, at best, imprecise and distort the urinary tract.” Hannah at col. 8, lines 40 to 47. It is, therefore, desirable to combine illumination with a balloon catheter to investigate in ways not envisioned by Hannah and areas not envisioned by Hannah. It would be desirable to focus all the illumination at a given place in a patient and in a desired direction so that as much light as possible illuminates the place where the surgeon desires and does not illuminate other areas, which illumination decreases the ability of the surgeon to identify the particular area to be investigated. 
         [0011]    For example, a common balloon catheter made by RUSCH® and referred to as a Foley catheter is widely used today for treating and draining a patient&#39;s bladder. The Foley catheter is shown in  FIG. 1  and has a multi-lumen shaft  1  that is disposed in the urethra  10 . A balloon portion  3  is disposed at the distal end of the shaft  1 , a fluid drain section  4  is disposed at the distal end of the balloon  3 , and a curved, distal guiding tip  5  is disposed at the distal-most end of the entire catheter. When placed properly, the proximal-most side of the inflated balloon  3  rests on the interior wall  31  of the bladder  30 , entirely blocking off the urethrovesical junction  11  connecting the bladder  30  and the urethra  10 . In such a position, the fluid drain section  4  allows continuous drainage of the bladder  30  and the balloon  3  virtually entirely prevents the catheter from slipping out of the bladder. This ideally inserted position is shown in  FIG. 1 . 
         [0012]    It is noted that use of the word “proximal” in the instant application refers to a direction towards the physician, which also corresponds to the bottom of the figures of the drawings. As such, use of the word “distal” in the instant application refers to a direction away from the physician, which also corresponds to the top of the figures of the drawings. 
         [0013]    As used herein, a fluid can be both a liquid and a gas. Exemplary fluids for inflating a balloon  3  are saline, air, or carbon dioxide gas. Exemplary fluids drained by the catheters mentioned herein include urine and blood. 
         [0014]    For placement of this catheter in the ideal position within the bladder  30 , however, the physician or technician has no visual aid. As diagrammatically illustrated in  FIG. 1 , the wall  40  defining the urethrovesical junction  11  is very short in the longitudinal direction of the urethra  10 . If the technician, nurse, or physician inserts the catheter too far into the bladder  30 , no damage occurs from balloon inflation; however, there is a possibility of leakage around the balloon  3 , which helps to lubricate the urethra  10  such that gentle proximal movement places the proximal side of the balloon  3  against the urethrovesical junction  11 . The bladder  30  can then easily expand and stretch to compensate for the balloon  3 . A normal bladder capacity is 400 to 500 cc. A normal balloon capacity is approximately 10 to 12 cc although larger balloons are sometimes used. 
         [0015]    The complication occurs when the technician and/or nurse inflates the balloon and in fact the balloon is not in the bladder. If the technician does not insert the catheter in far enough, then the balloon  3  will be subsequently inflated within the urethra  10 —a condition that is common and, not only is it to be avoided at all costs, is a frequent cause of bladder infections created during a hospital or clinic visit. Infections arise because inflation of the bladder  3  inside the urethra  10  causes the urethra  10  to stretch too far. Even though the urethra  10  is a flexible tube, it has limits to which it can be safely stretched from within. Almost every balloon catheter has an outer diameter/circumference that well-exceeds the safe stretching limit of the urethra  10 . Therefore, if the balloon catheter is not inserted far enough, inflation of the balloon  3  will cause serious injury to the urethra  10 . This is especially true with elderly patients who have urethra  10  that are not as elastic as younger patients. Tearing of the urethra  10  in this way causes bleeding and allows bacteria to enter into the bloodstream at the tear site, thus causing the subsequent bladder infection. 
         [0016]    In such a case, the balloon expands and tears the surrounding membrane called the mucosa. Tearing of the urethra  10  in this way causes bleeding and allows bacteria to enter into the bloodstream at the tear site, thus causing the subsequent bladder infection. Significant bleeding can become life threatening. The urethra can normally dilate several millimeters; however, when the balloon is inflated, this dilation is usually several centimeters. 
         [0017]    Over 96 million indwelling catheters are sold on an annual basis. Twenty four million catheters are sold to hospitals in the U.S. There are numerous complications associated with those catheters that need to be prevented. These complications are responsible for increases in hospital stays, excessive bleeding, mortality, as well as morbidity. This also causes an increased expense and burden on the already-stressed health care system. 
         [0018]    The complications result from several different mechanisms. First, and probably most common, is improper placement of the catheter. Because of the unique anatomy of the male urethra, placing a urethral catheter for urinary drainage can be difficult. A problem arises when the physician, technician, or nurse thinks that the catheter is actually in proper position. The proper position for the catheter is with the balloon being in the cavity of the bladder and the tip distal to the balloon is used to drain the bladder cavity. 
         [0019]    Life threatening bleeds, especially in patients who are anticoagulated, can and do occur. Also when the urine is infected, as in immunocompromised patients and the elderly, the bacteria, then, get into the blood stream and can cause serious infections called sepsis, which frequently can lead to death. If the patient survives the initial trauma, then long-term complications, such as strictures, can and usually do occur. Strictures are narrowings within the urine channel and usually require additional procedures and surgeries to correct. 
         [0020]    Other mechanisms of catheter-induced injuries are inadvertent manipulation of the tubing or dislodging of the balloon because the balloon is pulled due to a sudden jerk or tension. This usually happens when the patient is ambulating or traveling from the bed to the commode or bathroom. The tubing may inadvertently become fixed while the patient is still moving, at which time a sudden jerk is imparted upon the balloon and pulls the balloon into the urethra causing severe pain and bleeding. Injury caused by the improper, inadvertent, and/or early removal of an inflated balloon catheter is referred to as iatrogenic injury (also referred to as an in-hospital injury). 
         [0021]    Yet another scenario occurs when the patient deliberately pulls on the catheter, thereby causing self-induced pain and injury to the urethra. This commonly happens in confused patients, for example, patients in nursing homes who have a disease or cognitive dysfunction problem, such as Alzheimer&#39;s disease, or other diseases that make the patient unable to understand the necessity of having a catheter. Confusion occurs when the patient has a spasm causing a strong urge to urinate and pain. During the spasm, the confused patient often tugs and pulls on a catheter, which results in injury. 
         [0022]    These types of injuries are not limited to males and also cause severe damage to the female bladder and urethra. The injuries can also occur post-surgically, which makes the damage even more severe. One common situation where injury is cause is when the patient is medicated with morphine or other analgesics that render the patient confused and unable to make rational decisions. These injuries have been well documented and are not limited to adults. Numerous injuries are documented in pediatric patients. 
         [0023]    Usually, it takes time to make a diagnosis of patient-caused catheter injury. Immediately after diagnosing the injury, a technician needs to deflate the catheter. However, once the urethra is torn, replacing the damaged catheter with another catheter is quite difficult and, in fact, exacerbates the injury. Sometimes, the patient has to be taken to the operating room to replace a urinary drainage tube once this scenario occurs. Because catheters and leg bags are now used routinely in certain situations during home health care, this scenario is not limited to hospitals and occurs at nursing homes or the patient&#39;s home. 
         [0024]    Most of the recent catheter technology has been focused on reducing urinary tract infections that are caused by catheters, injuries that are usually the most common catheter-related complications. 
         [0025]    A balloon catheter made by TherMatrx, Inc. is used to treat Benign Prostatic Hyperplasia by treatment with THERMATRX® Dose Optimized Thermotherapy, a minimally invasive procedure performed in a urologist&#39;s office that uses heat delivered through a microwave antenna. A urethral catheter containing the microwave antenna is passed through the urethra and prostate gland and is secured by a balloon at the tip of the catheter that passes through the urethral sphincter. Localized microwave energy is delivered at a temperature high enough to relieve BPH symptoms, including difficult, frequent, or urgent urination. Features of such a catheter are also diagrammatically illustrated in  FIG. 1 . The catheter differs from the standard Foley catheter by the addition of a radiation coil  2  disposed at a distal end of the shaft  1  proximal to the balloon  3 . When placed properly, the radiation coil  2  is immediately adjacent and/or inside the prostate  20  and the proximal-most side of the inflated balloon  3  rests on the interior wall  31  of the bladder  30 , entirely blocking off the urethrovesical junction  11 . In such a position, the prostate  20  can be directly treated with the radiation coil  2 . This ideally inserted position is shown in  FIG. 1 . In use, correct placement of this catheter in the ideal position within the bladder  30  and near the prostrate  20  is the same as the Foley catheter—it is difficult and gives the physician or technician no visual aid. If the balloon  3  of the THERMATRX® catheter is not at the urethrovesical junction  11 , then the heating element  2  would not be in the proper position and subsequent heat damages an undesired area that can cause unintended injury. 
         [0026]    In a conventional balloon  3 , the balloon  3  has a substantially constant balloon wall thickness. The balloon  3  is fixed to the outer surface of a fluid drainage line (not illustrated in  FIG. 1 ) and is not intended to be removed therefrom or to burst thereon unless an extraordinary amount of inflation occurs. If such an event happens, the material of the balloon will open at a random location based upon the microscopic fractures or weaknesses in the material itself. Such a tearing event is not supposed to occur under any circumstances during use with a patient. 
         [0027]    Prior art catheters are not constructed to prevent tearing of the urethra during a catheter implanting procedure and are not constructed to break in any predefined way. Accordingly, it would be beneficial to provide a balloon catheter that does not inflate past the tearing limit of a urethra and breaks in a desired, predefined way under certain conditions. 
         [0028]    In a conventional balloon  3 , the balloon  3  has a substantially constant wall opaqueness—it is either fully transparent or it is semi- or fully-opaque (due to the natural properties of the balloon material). Accordingly, it would be beneficial to provide a balloon catheter that has differently placed regions of reflectivity and/or opaqueness to direct illumination from within the balloon catheter in a desired direction. 
       SUMMARY OF THE INVENTION 
       [0029]    It is accordingly an object of the present invention to provide a pressure-limiting balloon catheter and method for using the catheter that overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that does not inflate past the tearing limit of a lumen in which the catheter is placed, for example, in the urethra, and quickly and rapidly deflates if pulled out prior to deflation of the balloon. 
         [0030]    The purpose of the breakaway catheter of the present invention is to prevent injury by having the balloon automatically deflate before an injury can occur. While the catheter of the present invention makes it a safer device for urinary drainage, the present invention can also be used for any procedures in which balloons are used to dilate cavities. Examples of these procedures include coronary artery vessels, peripheral vascular vessels, such as the aorta and extremity vessels. Balloon dilations of other lumens, such as ureters and the esophagus, are also candidates for use of the catheter of the present invention. 
         [0031]    Although deflation of a catheter renders it useless, deflation protects the patient from serious harm. Prevention of such injuries is becoming more and more important because the injuries are commonplace. The increase occurs for a number of reasons. First, a greater percentage of the population is aging. Second, there is a current trend to use less-skilled health care personnel to perform more procedures and to be responsible for treatment, both of which save money. The shortage of nursing professionals (R.N.$) exacerbates this trend. The present tendency is to use nursing professionals for more functions, such as administration and delivery of medications. This leaves only the less-skilled technicians with the task of inserting catheters and taking vital signs. Under such circumstances, more injuries are likely. Lastly, catheter-related complications are becoming more severe due to the increased use of anticoagulation medication, such as Plavix™, that is frequently prescribed in treating cardiovascular disease. 
         [0032]    Yet another possible complication arising from the standard Foley catheter is that the balloon will not deflate even when the deflation mechanism is activated. This situation can occur, for example, because the wrong fluid is used to inflate the balloon, such as saline, which can crystallize. Sometimes, the ability to deflate the catheter is interrupted because the drainage channel that is used to deflate the balloon becomes obstructed, which is common if the catheter is left in place too long. Remedy of such a scenario involves an invasive procedure, which includes threading a needle or other sharp object somewhere through the body cavity to puncture the balloon and, thus, dislodge the catheter. 
         [0033]    With the breakaway catheter or auto-deflating balloon of the present invention, the technician, nurse, or doctor merely needs to actuate the deflation valve or pull on the catheter to cause the catheter to automatically deflate, thus sparing the patient from any additional surgical procedures. 
         [0034]    The added benefit of the present invention is not just for safety, significant financial benefits arise as well. 
         [0035]    It is believed that catheter-induced injuries are much more common than public documentation suggests. Catheter-related trauma occurs roughly at least once a week in a large metropolitan hospital. Usually, each incident not only increases the patient&#39;s hospital stay substantially, but also the expense of the stay. Each incident (which is usually not reimbursed by insurances) can increase the cost to the hospital thousands, even tens of thousands of dollars. 
         [0036]    When additional surgery is required to fix the catheter-induced injury, increased expense to the hospital is not only substantial, if litigation occurs as a result of the injury, damages awarded to the patient can run into the millions of dollars. The catheter of the present invention, therefore, provides a safer catheter that has the possibility of saving the medical industry millions of dollars. 
         [0037]    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 a balloon safety valve. 
         [0038]    The maximum stress that a typical urethra can take without tearing and/or breaking is known and is referred to as a maximum urethra pressure. It is also possible to calculate how much pressure is exerted upon the exterior of a balloon of a balloon catheter by measuring the pressure required to inflate the balloon. Knowing these two values, it is possible to construct a balloon that breaks rapidly and/or ceases inflation if the maximum urethra pressure is exceeded. 
         [0039]    For example, in a first embodiment, the balloon, which is typically some kind of rubber, silicone, or plastic, can be made with a breaking point that instantly deflates the balloon if the pressure in the balloon exceeds the maximum urethra pressure. It is acknowledged and accepted that, once the balloon breaks, this catheter is useless and must be discarded because the cost of injury far outweighs the cost of the disposable catheter. Also, such a balloon is limited to inflation with a bio-safe fluid to prevent unwanted air/gas from entering the patient. If, however, air will not injure the patient, the fluid can be air. 
         [0040]    As an alternative to a one-use breaking safety valve, a multi-use pressure valve can be added to the balloon inflation lumen and can be set to open into the environment (instead of in the patient) if the maximum urethra pressure exceeded in the balloon or the balloon inflation lumen. Such a valve can be located near or at the balloon inflation port and, in such a configuration, will not enter improperly the patient. Any combination of the above valves is envisioned as well. 
         [0041]    With the foregoing and other objects in view, there is provided, in accordance with the invention, a breakaway catheter, including a multi-lumen shaft having a distal end, a hollow balloon portion disposed at the distal end of the shaft, the balloon portion having a distal end and an interior, and at least one of the shaft and the balloon portion having a balloon safety valve formed to open to the environment outside the at least one of the shaft and the balloon portion when greater than a given bursting pressure exists within at least one of the shaft and the interior of the balloon portion. 
         [0042]    In accordance with another feature of the invention, the shaft defines a fluid drain lumen and a balloon inflation lumen fluidically connected to the interior of the balloon portion, and the balloon safety valve is formed to open to the environment outside at least one of the shaft and the balloon portion when greater than a given bursting pressure exists within at least one of the balloon inflation lumen and the interior of the balloon portion. 
         [0043]    In accordance with a further feature of the invention, the shaft has a proximal end defining a balloon port fluidically connected to the balloon inflation lumen and an inflating connector is fluidically connected to the balloon inflation lumen through the port. 
         [0044]    In accordance with an added feature of the invention, the inflating connector is at least a portion of a luer connector. 
         [0045]    In accordance with an additional feature of the invention, the proximal end of the shaft defines a fluid port fluidically connected to the fluid drain lumen. 
         [0046]    In accordance with yet another feature of the invention, there is provided a fluid drain disposed at the distal end of the balloon portion and fluidically connecting the fluid drain lumen to the environment at the fluid drain and the fluid port to the environment at the proximal end of the shaft. 
         [0047]    In accordance with yet a further feature of the invention, the fluid drain has a curved, distal guiding tip. 
         [0048]    In accordance with yet an added feature of the invention, the balloon safety valve is at the balloon portion and is fluidically connected to the interior of the balloon portion. 
         [0049]    In accordance with yet an additional feature of the invention, the balloon safety valve is integral with the balloon portion. 
         [0050]    In accordance with again another feature of the invention, the balloon safety valve is at the shaft and is fluidically connected to the interior of the balloon portion. 
         [0051]    In accordance with again a further feature of the invention, the balloon safety valve is integral with the shaft. 
         [0052]    In accordance with again an added feature of the invention, the balloon safety valve is removably attached to the shaft. 
         [0053]    In accordance with again an additional feature of the invention, the balloon inflation lumen and/or the balloon portion has a material breaking point formed to break and deflate the balloon portion when pressure in at least one of the balloon inflation lumen and the balloon portion exceeds the given pressure. 
         [0054]    In accordance with still another feature of the invention, the given pressure is a maximum urethra pressure. 
         [0055]    In accordance with still a further feature of the invention, the balloon portion has a wall thickness and the balloon safety valve is a defined reduction in the wall thickness. 
         [0056]    In accordance with still an added feature of the invention, the reduction has a shape selected from one of the group consisting of a hemisphere, a cylinder, a groove, a trapezoid, a triangle, a square, a rectangle, a pyramid, and frusto-conical. If the reduction is a groove, then the groove can be formed to extend partly around the balloon portion. 
         [0057]    In accordance with still an additional feature of the invention, the shaft defines a balloon inflation lumen fluidically connected to the interior of the balloon portion, the shaft has an outer surface, and the defined reduction is a narrowing of a wall thickness between the balloon portion and the environment and/or the balloon inflation lumen and the outer surface of the shaft. 
         [0058]    In accordance with another feature of the invention, the balloon inflation lumen and the outer surface define a wall therebetween, and the defined reduction is a narrowing of a thickness of the wall from the outer surface towards the balloon inflation lumen and/or from the balloon inflation lumen towards the outer surface. 
         [0059]    In accordance with a further feature of the invention, the shaft has a wall thickness and the balloon safety valve is a defined reduction in the wall thickness. 
         [0060]    In accordance with an added feature of the invention, the balloon safety valve opens into the environment and/or a patient when broken. 
         [0061]    In accordance with an additional feature of the invention, the balloon safety valve is formed to burst at a first breaking force less than a second breaking force required to burst at least one of the balloon portion and the shaft. 
         [0062]    In accordance with yet another feature of the invention, at least one of the balloon portion and the shaft is formed to burst at a first breaking force and the balloon safety valve is formed to burst at a second breaking force less than the first breaking force. 
         [0063]    With the objects of the invention in view, there is also provided a breakaway catheter, including a multi-lumen shaft having a distal end, a hollow balloon portion disposed at the distal end of the shaft, the balloon portion having a distal end and an interior, and at least one of the shaft and the balloon portion having a balloon safety valve formed to burst at a first breaking force less than a second breaking force required to burst at least one of the balloon portion and the shaft. 
         [0064]    With the objects of the invention in view, there is also provided a pressure-limiting balloon catheter, including a multi-lumen shaft having first and second lumen each shaped to pass a respective fluid therethrough, a hollow balloon portion defining an interior chamber fluidically connected to the first lumen for receiving fluid therein to inflate and deflate at least a part of the balloon portion, and a pressure-limiting valve fluidically connected to at least one of the balloon portion and the first lumen, the valve opening to the environment of at least one of the shaft and the balloon portion when greater than a given bursting pressure exists in the least one of the balloon portion and the first lumen. 
         [0065]    With the objects of the invention in view, there is also provided a pressure-limiting balloon catheter, including a multi-lumen shaft having a balloon inflation lumen shaped to pass a balloon-inflating fluid therethrough and a catheter lumen shaped to pass a fluid therethrough, a hollow balloon portion defining an interior chamber fluidically connected to the balloon inflation lumen for receiving the balloon-inflating fluid therein to inflate and deflate at least a part of the balloon portion, and a pressure-limiting valve fluidically connected to at least one of the balloon portion and the balloon inflation lumen, the valve opening to the environment of at least one of the shaft and the balloon portion when greater than a given bursting pressure exists in the least one of the balloon portion and the balloon inflation lumen. 
         [0066]    With the objects of the invention in view, there is also provided a breakaway catheter kit, including a set of breakaway catheters according to the present invention, each of the catheters having the balloon safety valve with different safety valve breaking constants. 
         [0067]    It is accordingly a further object of the present invention to provide an illuminating balloon catheter and method for using the catheter that overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that focuses a substantial amount of illumination at a given place in a patient and in a desired direction so that as much light as possible illuminates the place where the surgeon desires and does not illuminate other areas and to do so with a balloon of a balloon catheter. 
         [0068]    The present invention relates to a catheter that has a light system incorporated therein that illuminates the organ from the inside. For example, a urethra balloon catheter can have a light source on the balloon and, when the balloon is inflated in the bladder and the light is turned on, the inflated bladder acts as a light source having a relatively spherical shape dependent upon the directionality of the light source (uni-directional, multi-directional, omni-directional). 
         [0069]    As described above, Hannah uses omni-directional light for locating the urethrovesical junction in a gynecological procedure referred to as the Marshall-Marchetti-Kranz (MMK) procedure. While it is true that some prior art devices like Hannah use illumination to identify regions in a patient, they do not combine directional illumination with a balloon catheter because, to do so, would not allow the prior art devices to perform their intended purpose—eliminate the need to orient the fiber optic angularly within the catheter. Specifically, these devices do not and cannot focus light in a particular desired direction, i.e., they only provide omni-directional illumination. 
         [0070]    The invention of the instant application provides directionally guided illumination of a balloon catheter when inside a patient. When a physician is operating on a bladder or a prostate, for example, it is difficult to locate particular areas on the organ that are of interest to the physician. One example procedure requires the location of the junction between the prostate and the bladder, referred to as the urethrovesical junction. Typical operations for the bladder and prostate are laparoscopic, meaning that a small incision is made in the torso of the patient and instruments are inserted through these incisions for carrying out the operation. The physician, therefore, remotely operates on the organ using a viewing system inserted through the incision. Sometimes, the light shining from one part of the laparoscope is insufficient for locating a desired area, primarily because it is shining the light from outside the urethra, prostate, and bladder. Thus, reflection and tissue density prevent optimal location of a desired tissue region. It would be desirable, in some instances, to improve upon such lighting measures. 
         [0071]    The balloon catheter according to the invention lights the organ from the inside (preferably, while lowering or shutting off the light of the laparoscope) and, therefore, gives the physician a different perspective. In such a case, the physician sees structures in and/or on the hollow organ, but illuminated from within the organ. Interior lighting allows the physician to better locate the urethrovesical junction. 
         [0072]    When prostate cancer is detected in a patient, a laparoscopic prostatectomy is carried out to remove the prostate and seminal vesicles. It is self-evident that, during a laparoscopic prostatectomy, it is critical to identify the junction between the prostate and the bladder because error in detecting the junction may result in undesired removal of necessary body tissue. Failure to identify the urethrovesical junction clearly, therefore, is quite serious. Performing the procedure correctly requires clear identification of the urethrovesical junction without error. If the prior art omnidirectional illuminating devices are used, the light emitting in all directions except towards the urethrovesical junction diminishes the ability of the physician to carry out the laparoscopic prostatectomy. 
         [0073]    With the invention of the instant application, the ability to location the junction is improved, not diminished. The illuminating balloon of the present invention is inflated in the bladder and the surgeon or assistant rotates the catheter using the directional light to help locate this junction, in a similar way to illumination from a lighthouse. 
         [0074]    Inflation of the balloon to have the proximal portion thereof press against the wall of the bladder near the urethrovesical junction to compress the tissue there allows the urethrovesical junction to be very apparent when viewed through a laparoscope. In combination with the compression of the urethrovesical junction, the directed illumination from the fiber optic according to the present invention allows the metes and bounds of the urethrovesical junction to be clearly identified. Accordingly, success rates of laparoscopic prostatectomy, for example, will increase. 
         [0075]    The light source can either be inside the balloon (in which case at least a portion of the balloon corresponding to the light-emitting area is transparent), on the balloon surface, or near the tip of the catheter distal of the balloon. The present invention combines the inflation of the balloon with the directional illumination to illuminate areas during surgical procedures. 
         [0076]    In one embodiment of the illuminating catheter of the present invention, portions of the balloon can have a reflective coating so that light is directed (in the manner of a lighthouse) only in a given direction, or a set of given directions. 
         [0077]    When a Foley catheter (or other urethral catheter) is inserted properly for a laparoscopic prostatectomy, the urethrovesical junction should be directly opposite the tip  5  of the catheter. In such a configuration, it is desirable if all the illumination is directed back towards the shaft  1  (in a proximal direction) and illumination in the distal direction is entirely prevented. Thus, a reflective coating is placed on the inside or outside surface of the balloon such that, when the balloon is inflated and is illuminated from within, all illumination is directed proximally. 
         [0078]    A hemispherical coating is one variant for proximally directing such illumination. Depending on the lateral distance away from the urethrovesical junction that the physician wishes to view, the reflective coating can be merely present on the distal hemi-spherical half of the balloon or it can extend further in the proximal direction along the surface of the balloon. For example, the reflective surface can be disposed on ⅔rds of the sphere of the balloon such that only ⅓ of the surface area of the balloon allows illumination in the proximal direction. 
         [0079]    Further, because the physician views the urethrovesical junction from only one side thereof, there may not be a need to illuminate the “back” half of the urethrovesical junction with respect to the viewing side of the physician. In other words, there is a need to only view the “front” side with the illumination—the side of the urethrovesical junction at which the physician is looking. In such a case, the urethrovesical junction will be illuminated particularly well to the exclusion of all other prostate-urethra-bladder structures if the directional illumination catheter of the present invention is used. 
         [0080]    The reflective surface of the present invention can be disposed on the interior of the balloon or on the exterior thereof, or both. Also, instead of a reflective coating, the balloon can have a substantially opaque portion and a substantially transparent portion—the latter being disposed at the balloon to direct illumination in the desired direction and the former being disposed at the balloon such that light does not emanate in any direction at which illumination is not desired. In such a configuration, the reflective surface can be complemented with or separate from the opaque/transparent configuration. For example, the reflective surface can be in the interior of the balloon with a transparent portion corresponding to/aligned with the balloon portion not having the reflective surface and with an opaque portion corresponding to the location/surface area of the reflective surface. 
         [0081]    These lighting systems can be articulated (i.e., rotationally displaced) so that the physician can adjust the direction of the light. 
         [0082]    Many lighting configurations are possible. One example configuration includes a fiber optic strand or bundle of strands that terminate in the balloon, similar to the single strand of Hannah. Accordingly, U.S. Pat. No. 4,248,214 to Hannah et al. is herewith incorporated by reference herein in its entirety. Another example includes a light-emitting diode (LED) disposed in or on the balloon. 
         [0083]    With the foregoing and other objects in view, there is provided, in accordance with the invention, a directionally illuminating balloon catheter, including a multi-lumen shaft having a distal end and a hollow balloon portion disposed at the distal end and inflated through the shaft, the balloon portion having a light source illuminating only a portion of the environment outside the balloon portion. 
         [0084]    With the objects of the invention in view, there is also provided a directionally illuminating balloon catheter, including a multi-lumen shaft having a distal end and a hollow balloon portion disposed at the distal end and inflated through the shaft, the balloon portion having a directionally limited light source. 
         [0085]    With the objects of the invention in view, there is also provided a directionally illuminating balloon catheter, including a multi-lumen shaft having a distal end, and a hollow balloon portion disposed at the distal end and inflated through the shaft, the balloon portion having a light source directing substantially all illumination towards the shaft. 
         [0086]    With the objects of the invention in view, there is also provided a catheter kit, including a set of directionally illuminating catheters, each of the catheters having the light source with different sized illuminating areas to illuminate a different sized partial portion of the environment outside the balloon portion. 
         [0087]    In accordance with another feature of the invention, the balloon portion has an interior, and the shaft defines a fluid drain lumen and a balloon inflation lumen fluidically connected to the interior of the balloon portion. 
         [0088]    In accordance with a further feature of the invention, the light source is connected to the interior of the balloon portion through at least one of the fluid drain lumen and the balloon inflation lumen. 
         [0089]    In accordance with an added feature of the invention, the shaft further defines an illumination device lumen and the light source is connected to the interior of the balloon portion through the illumination device lumen. 
         [0090]    In accordance with an additional feature of the invention, the shaft has a proximal end defining a balloon port fluidically connected to the balloon inflation lumen and an inflating connector is fluidically connected to the balloon inflation lumen through the balloon port. 
         [0091]    In accordance with yet another feature of the invention, the inflating connector is at least a portion of a luer connector. 
         [0092]    In accordance with yet a further feature of the invention, the proximal end of the shaft defines a fluid port fluidically connected to the fluid drain lumen. 
         [0093]    In accordance with yet an added feature of the invention, the balloon portion has a distal end and a fluid drain is disposed at the distal end of the balloon portion and fluidically connects the fluid drain lumen to the environment at the distal end. The fluid drain can have a curved, distal guiding tip. 
         [0094]    In accordance with yet an additional feature of the invention, the light source illuminates only approximately a proximal half of the environment outside the balloon portion. 
         [0095]    In accordance with again another feature of the invention, the light source illuminates only approximately half of the proximal half of the environment outside the balloon portion. 
         [0096]    In accordance with again a further feature of the invention, the light source only illuminates a partial asymmetrical portion of the environment outside the balloon portion. 
         [0097]    In accordance with again an added feature of the invention, the balloon portion has different regions of reflectivity and opaqueness to direct illumination from within the balloon portion into a given area outside the balloon portion. 
         [0098]    In accordance with again an additional feature of the invention, the balloon portion is of a material and the regions of reflectivity and opaqueness are a natural property of the material. 
         [0099]    In accordance with still another feature of the invention, the balloon portion has an at least semi-transparent portion for transmitting light out from the balloon portion through the transparent portion and an opaque portion for preventing transmission of light out from the balloon portion through the opaque portion. 
         [0100]    In accordance with still a further feature of the invention, the balloon portion has a proximal side facing the shaft, the shaft and the balloon portion form a urethral catheter, and the light source illuminates substantially only a urethrovesical junction when the proximal side of the balloon portion is adjacent the urethrovesical junction. 
         [0101]    In accordance with still an added feature of the invention, the light source is inside and/or outside the balloon portion. 
         [0102]    In accordance with still an additional feature of the invention, the balloon portion has an interior, and at least one portion of the interior has a reflective coating to direct light emanating from the balloon portion. 
         [0103]    In accordance with another feature of the invention, the coating is integral with the balloon portion. 
         [0104]    In accordance with a further feature of the invention, the coating is disposed on the balloon portion. 
         [0105]    In accordance with an added feature of the invention, the light source directs substantially all illumination towards the shaft. 
         [0106]    In accordance with an additional feature of the invention, the light source transmits substantially no illumination out from the balloon portion opposite the shaft. 
         [0107]    In accordance with yet another feature of the invention, the balloon portion has an interior and the light source rotates within the interior of the balloon portion in the manner of a lighthouse. 
         [0108]    In accordance with yet a further feature of the invention, the light source directs light only in a given direction. 
         [0109]    In accordance with a concomitant feature of the invention, the light source is selected from at least one of the group consisting of a fiber optic, a light-emitting diode, an organic light-emitting diode, and a combination of the fiber optic, the light-emitting diode, and the organic light-emitting diode. 
         [0110]    Other features that are considered as characteristic for the invention are set forth in the appended claims. 
         [0111]    Although the invention is illustrated and described herein as embodied in an illuminating balloon catheter and method for using the catheter, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0112]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS: 
         [0113]      FIG. 1  is a longitudinally diagrammatic cross-sectional view of a prior art catheter ideally placed in a urethra and a bladder of a male patient; 
           [0114]      FIG. 2  is a fragmentary, enlarged, cross-sectional view of a distal portion of a first embodiment of a pressure-limiting balloon catheter according to the invention; 
           [0115]      FIG. 3  is a fragmentary, enlarged cross-sectional view of a proximal portion of a second embodiment of a pressure-limiting balloon catheter according to the invention; 
           [0116]      FIG. 4  is a fragmentary, enlarged, cross-sectional view of a first alternative configuration of the safety valve of  FIG. 3 ; 
           [0117]      FIG. 5  is a fragmentary, enlarged, cross-sectional view of a second alternative configuration of the safety valve of  FIG. 3 ; 
           [0118]      FIG. 6  is a fragmentary, enlarged, cross-sectional view of a third alternative configuration of the safety valve of  FIG. 3 ; 
           [0119]      FIG. 7  is a fragmentary, further enlarged, cross-sectional view of the safety valve of  FIG. 6 ; 
           [0120]      FIG. 8  is a fragmentary, further enlarged, cross-sectional view of a fourth alternative configuration of the safety valve of  FIG. 3 ; 
           [0121]      FIG. 9  is a fragmentary, perspective view of a fifth alternative configuration of a retrofitting safety valve according to the invention; 
           [0122]      FIG. 10  is a fragmentary, enlarged, cross-sectional view of a distal portion of a first embodiment of an illuminating balloon catheter according to the invention; 
           [0123]      FIG. 11  is a fragmentary, enlarged cross-sectional view of a proximal portion of the catheter of  FIG. 10 ; 
           [0124]      FIG. 12  is a fragmentary, enlarged, cross-sectional view of a first configuration of a reflective balloon of the catheter of  FIGS. 10 and 11 ; 
           [0125]      FIG. 13  is a fragmentary, enlarged, cross-sectional view of a second configuration of a reflective balloon of the catheter of  FIGS. 10 and 11 ; 
           [0126]      FIG. 14  is a fragmentary, enlarged, cross-sectional view of a second embodiment of the illuminating balloon catheter according to the invention; 
           [0127]      FIG. 15  is a fragmentary, enlarged, cross-sectional view of a third embodiment of the illuminating balloon catheter according to the invention; 
           [0128]      FIG. 16  is a fragmentary, enlarged, cross-sectional view of a fourth embodiment of the illuminating balloon catheter according to the invention; and 
           [0129]      FIG. 17  is a fragmentary, enlarged, cross-sectional view of a fifth embodiment of the illuminating balloon catheter according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0130]    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. 
         [0131]    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. 
         [0132]    Referring now to the figures of the drawings in detail and first, particularly to  FIG. 2  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. 
         [0133]    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  FIG. 1 ), the balloon  3  is fixed to the outer surface of the fluid drainage line  120  (not shown in  FIG. 1 ) 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. 
         [0134]    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. 
         [0135]    In the embodiment shown in  FIG. 2 , 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  FIG. 2 , 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 . 
         [0136]    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 . 
         [0137]    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. 
         [0138]    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. 
         [0139]    A second embodiment of the one-use breaking safety valve of a pressure-limiting balloon catheter  200  is shown in  FIG. 3 . The catheter  200  has a fluid drainage line  220 , a balloon inflation lumen  230 , and a secondary lumen  240 . 
         [0140]    The fluid drainage line  220  is connected fluidically to the body cavity (i.e., the bladder  30 ) for draining fluid from the body cavity. 
         [0141]    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. 
         [0142]    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. 
         [0143]    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. 
         [0144]    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  FIG. 3 , the valve  212  has a rectangular cross-section and extends away from the balloon inflation lumen  230 . As shown in  FIGS. 4 ,  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  FIGS. 3 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. 
         [0145]    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  FIG. 7 . 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). 
         [0146]    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. 
         [0147]    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. 
         [0148]    One embodiment of the attachment is illustrated in  FIG. 9 . 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  FIG. 9 . A common exemplary inflation device  280  is a syringe. 
         [0149]    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. 
         [0150]    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  FIG. 8 . The catheter  300  can be the same as the catheter  200  in FIG.  3  except for the portion illustrated in  FIG. 8 . 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  FIG. 8 ) 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. 
         [0151]    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. 
         [0152]    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  FIG. 2  can also be used for redundant over-pressure protection. 
         [0153]    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. 
         [0154]    Referring now to  FIG. 10  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 . 
         [0155]    The catheter body  102  defines a fluid drainage lumen  120 , a balloon inflating lumen  130 , and an illumination device lumen  140 . 
         [0156]    The distal end of the drainage assembly  150  is explained below with regard to  FIG. 12  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 . 
         [0157]    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  FIG. 11 . 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 . 
         [0158]      FIG. 11  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 . 
         [0159]    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  FIG. 11  diagrammatically with dashed lines. 
         [0160]    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. 
         [0161]    The illumination device lumen  140  is formed to house a directional illumination source  201 , shown (in a first embodiment in  FIG. 12 ) 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  FIG. 11 . 
         [0162]    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 . 
         [0163]    In  FIG. 12 , 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  FIG. 12 ). 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. 
         [0164]    In the hemispherical shape of  FIG. 12 , 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 . 
         [0165]    As shown, for example, in  FIG. 13 , 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  FIG. 13 , 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. 
         [0166]    A second embodiment of the illuminating balloon catheter is shown in  FIG. 14 . 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 . 
         [0167]    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  FIG. 15 . In this configuration, the secondary lumen  140  becomes available for another useful purpose. 
         [0168]      FIG. 16  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. 
         [0169]      FIG. 17  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  FIG. 12  (but not shown in  FIG. 17 ). 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 . 
         [0170]    Laparoscopic prostatectomy can be assisted with all of the configurations shown in  FIGS. 12 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. 
         [0171]    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  FIGS. 4 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. 
         [0172]    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.