GB2492643A - Urological catheter with inflatable bladder located in catheter walls - Google Patents

Abstract

There is provided a catheter comprising a plastic tube having a distal end, for insertion into the urethra, and a proximal end, wherein an inflatable bladder 32 is defined within the walls 44 of the catheter. The internal bladder may be connected to a fluid pump via an internal conduit 42. The inflatable section inside the walls may be reinforced by braiding, and may have a ribbed external configuration. The urethral catheter may have a coating such as polyanhydride or polyorthoester which are subject to degradation. The catheter may be used in cases of urethral stricture.

Description

Imirovements in or relating to Urological Catheters

Field of the Invention

The present invention relates to catheters, particularly urological catheters, suitable for use by male and female humans and other animals.

Backaround to the Invention

The bladder is part of a body's urinary system that filters waste products out of the blood and produces urine. The bladder is a hollow organ of variable capacity and consists of several layers. The inside of the bladder has a special type of lining, called the transitional epithelium that stretches as the bladder fills up and prevents urine from leaking into the body. The bladder also has a powerful intermediate muscle coat that empties the organ through a urethra, when it contracts. The urinary sphincter, also referred to as the urethral sphincter, is a series of muscles that contract around the urethra in order to achieve bladder control. An internal urinary sphincter prevents flow of urine through the urinary tract from the bladder and the external urinary sphincter provides additional voluntary control. Weakness or malfunction of these muscles can lead to urinary incontinence.

A catheter can be required following surgery to the lower abdomen, arising from post-operative swelling which causes a urethral stricture -a narrowing of the urethra. Equally a urethral stricture may be caused by injury or disease. The stricture usually develops as scar tissue over a period of time. Approximately 600/c of urethral strictures are caused by trauma, injury or other causes including previous catheter use and infection (Mathur, 2010). Indeed, the chief disorders necessitating the employment of the catheter in the male animal comprise retention of urine from stricture, enlargement of the prostate gland, the presence of calculi, injuries to the penis, morbid growths, inflammation of the bladder, and paralysis. Patients with urethral strictures often experience pain during urination and an inability to completely empty the bladder. In some cases the stricture may result in a complete inability to urinate. Currently the main forms of treatment are surgical urethroplasty, Optical internal urethrotomy and urethral dilation.

Optical internal urethrotomy involves surgically removing the portion of the stricture that is causing the blockage. This is usually carried out under S general anaesthetic using a cystocope and surgical tools introduced down the length of the urethra. Urethroplasty involves surgically repairing the urethra by removing the strictured length. Again performed under general anaesthetic and is an open surgery procedure. Urethral dilation can be performed by the use of a solid dilating catheter, pushed through the stricture to stretch the scar tissue under general anaesthetic, by the use of an axially inserted catheter, which remains in position (known as an in-dwelling catheter) or is used only during urination (known as an intermittent catheter and is typically a disposable catheter), in each case the catheter stretching the urethra to enable draining of the bladder.

In urinary catheterization, a plastics tube, manufactured from, for example one of latex, polyurethane or silicone, known as a urinary catheter is inserted into a patient's bladder via his or her urethra. Such catheterization allows the patient's urine to drain freely from the bladder for collection. In males, the catheter tube is inserted into the urinary tract through the penis; in females, the catheter is inserted into the urethral meatus. A cleansing agent such as a mild antiseptic, for example, a mild iodine solution, anti-bacterial wipes or similar can be used. Catheterization should be performed as a sterile medical procedure and should only be done by trained, qualified personnel, using equipment designed for this purpose, except in the case of intermittent self catheterization where the patient has been trained to perform the procedure himself.

Common indications to catheterize a patient include acute or chronic urinary retention -(which can damage the kidneys), orthopaedic procedures that may limit a patient's movement, the need for accurate monitoring of input and output (such as in an ICU), benign prostatic hyperplasia, incontinence, and the effects of various surgical interventions involving the bladder and prostate. However, one of the more common reasons for the need of catheterization, is the need to stretch the urinary sphincter to allow a freer flow of urine. The catheter is also used when the patient has undergone Trans-Urethral Resection of the Bladder and Cystectomy with bladder reconstruction.

Self catheterization catheters are designed to allow the patient, following medical supervisory instruction, to insert the catheter in their home S environment. These catheters are of a fixed circumference and are inserted via the urethra into the bladder sphincter to achieve an enlargement or to maintain the current aperture of the sphincter.

Intermittent self catheterization will be performed by the user up to 6 times a day using a clean technique in most cases. If correct technique is not used there may be trauma to the urethra or prostate (male), urinary tract infection, or a paraphimosis in the uncircumcised male. In addition to the clinical benefits, patient quality of life is enhanced by the increased independence and security offered by self catheterization. Notwithstanding the above, the use of the catheter carries an inherent risk of causing a bladder infection and therefore the patient following the insertion of one catheter would not normally be advised to insert a second one of increased circumference to achieve further stretching of the sphincter aperture.

Additionally, in certain circumstances, a fixed circumference catheter cannot be inserted through the urethra past the sphincter and the bladder cannot be emptied; the patient will typically be referred for a cystoscopy with the potential need for surgical treatment as a means of enlarging the sphincter aperture to relieve the problem. In the case of certain patients, scar tissue grows around the area of the sphincter, calling for a further round of surgery with the potential for the bladder sphincter to become further weakened, leading to the patient becoming permanently incontinent. At present, a patient, further to evaluation by their medical advisor can only be prescribed a self administered catheter of a fixed circumference and will be told to continue use under frequent review. The urethra is the opening that allows urine to leave the bladder. In men, the urethra is a thin tube-like structure that starts from the lower opening of the bladder and traverses the entire length of the penis. In women, it is a shorter opening coming off the lower opening of bladder and is between 2.5 to 4 centimetres (cm) in length.

In animals, such as bulls, cows, horses and pets such as dogs, catheterization procedures, administered by veterinarians, can be followed. Depending on the size of animal, the diameter of the catheter S can be large -for example, in the case of a stallion, the length can be more than a metre and the diameter as much as 13mm or more.

Object of the Invention The present invention seeks to provide a solution to at least some of the problems identified above.

The present invention seeks to provide an improved catheter which can overcome or ameliorate the above problems.

Statement of the Invention

In accordance with a first aspect of the invention, there is provided a catheter comprising a length of plastics tube having a distal end, for insertion into the urethra, and a proximal end, wherein an inflatable section or balloon is defined within the walls of the catheter and is positioned along the length of the catheter, the inflatable section communicating to the proximal end of the catheter via an internal conduit, the conduit terminating in an adaptor for attachment to a fluid pump, wherein in use and operably positioned within a urethra, the inflatable section can be inflated whereby to increase the diameter of the inflatable portion from an un-inflated state to an inflated state.

Conveniently, the adapter of the catheter is connected to a fluid pump, whereby the pump can increase the size of the inflatable section. In use, the inflatable section is positioned adjacent the sphincter or other occlusion; upon inflation the inflatable section can urge the sphincter or other occlusion further open and gently abrade the walls of the sphincter or other occlusion. Preferably, an initial catheter employed is of a first, small diameter; in subsequent use, conveniently after 3 -6 uses of a narrow catheter, the size of catheter can be increased; after increasing the size, in stages, during subsequent procedures, the sphincter or other occlusion can allow an increase in volumetric flow of fluid. Additionally, gentle use of the catheter has been found to discourage scar tissue growth.

The catheter inflatable section can be positioned at a distance of 20 -50 mm from the distal end. Conveniently, for example with regard to a S prostate enlargement, the inflatable section extends over a length of 40 - 80mm, conveniently extending beyond the prostate gland, at each end, of the urethra. For disease of the urethra as such, for example when a condition such as gonorrhoea exists, the inflatable section may extend substantially along the whole length of the urethra. Braiding within the outer wall of the inflatable section can prevent a non-uniform increase in diameter of the inflatable section.

Conveniently, the un-inflated diameter of the inflatable section of the catheter is in the range of 4 -8 mm. Conveniently, the inflated diameter of the inflatable section of the catheter is in the range of 15 -25mm.

The catheter may also be provided with a liquid flow conduit from the distal end to the proximal end, whereby to allow bladder drainage during a procedure. The catheter inflatable section may define an external axially ribbed configuration. The catheter inflatable section may define an external screw-like ribbed configuration. Such a configuration may further facilitate opening of the sphincter.

It will be realised that the circumference of the device is smaller than catheters currently available so that it can easily enter regions of partial occlusion of the urethra as defined by the sphincter or other occlusion.

Accordingly, for example, the catheter has a better chance of entering a reduced diameter sphincter that normally would not permit the passage of currently available devices. Conveniently, the catheter has markings whereby it is possible to determine the extent of insertion within the urethra. Present catheters are of a fixed size; if the fixed size is not able to pass the obstruction, then a catheter has to be fitted under anaesthetic.

In addition, catheters fixed by the physician have a retaining means such as flaps or a balloon that sit in the bladder holding the catheter in place.

Since the sphincter cannot shut properly with catheter in place this will give rise to the possibility of infection entering the bladder. This type of infection is very common and difficult to overcome with the known systems. The present invention thereby provides a further advantage in that it can be made such that it has a small diameter and can therefore pass urethral obstructions. Once in place it can be inflated to allow the urine to flow and can be removed once the bladder has been emptied.

The user is able to carry out this process, following diagnosis and simple instruction regarding the placement of the present invention.

In another aspect of the invention, there is provided a catheter, especially operable as a short term in-dwelling catheter, with a coating which degrades in a very controlled and uniform manner so as to substantially preclude the possibility of sizeable particles becoming detached and possibly causing problems. This is achieved by employing a material in the coating of the catheter that erodes in a very controlled manner. Such material being selected for its tendency to erode from the surface inwardly, rather than being subject to bulk erosion. By incorporating pharmacological agents within the material, the catheter coating not only eventually vanishes from within the body lumen in which it was implanted but additionally dispenses the incorporated pharmacologicai agent in a gradual manner. The inflatable section of the catheter can assist in retention of the catheter whilst in position and topical application of a drug can conveniently be enabled, for example, to treat diseases such as gonorrhoea, where at least apportion of the urethra is infected. Equally, palliative substances may also be dispensed.

Materials that exhibit the desired surface eroding characteristics without being subject to bulk erosion include polymers wherein the degradation rate of the matrix is faster than the rate of water penetration into the interior of the polymeric mass. Such polymers are hydrophobic but have water-labile linkages interconnecting the monomers. The hydrophobic property precludes water from penetrating into the interior of the polymer while water-labile linkages nonetheless subject the surface to gradual erosion. As a result, the catheter coating gradually degrades from the surface inwardly, substantially without the risk of large particles becoming dislodged.

While hydrophobic polymers with water-labile linkages are known, their limited strength and processing capabilities have restricted their usage to passive devices that neither perform a structural function nor are subject to stress or distortion. Drugs infused throughout such material implanted in the body in the form of a tablet or other shape are gradually released as the polymer degrades. The materials employed in coating a catheter in accordance with the present invention include hydrophobic polymers having water-liable linkages connecting the monomers that are fortified with the incorporation of ester or imide bonds. Examples of such polymers include polyanhydrides and polyorthoesters. Additionally, by employing such polymers in catheter applications, a single device can be called upon to provide the necessary dilation to a urethra and simultaneously dispense a pharmacological agent in a controlled manner.

Brief description of the Figure

Some preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 shows a cross-section through the lower abdomen of a male; Figure 2 shows an embodiment of the invention in use; Figure 3 show an example of a first embodiment of the invention; Figures 3a and 3b shows a second embodiment of the invention having an elongate bladder and example of braid used in the inflatable section outer wall; Figures 4a and 4b shows a distal part of a catheter in accordance with the invention before and after inflation; Figures 4c and 4d shows two types of stilet; and, Figures 5 and 6 show a second embodiment of the invention, before and after inflation.

Detailed Description of the Preferred Embodiments

There will now be described, by way of example only, the best mode contemplated by the inventor for carrying out the present invention. In the following description, numerous specific details are set out in order to provide a complete understanding to the present invention. It will be apparent to those skilled in the art, that the present invention may be put into practice with variations of the specific.

S Figure 1 shows a cross-section through the lower abdomen of a male human. The bladder 28 can be seen as a central portion which drains through a urethra 22, which passes through the penis 24. A urinary sphincter muscle 18 closes and opens a sphincter 30, operable to control passage of fluid through the urethra. Any inflammation of the urethra can result in scarring, which then can lead to a stricture or a narrowing of the urethra. Trauma, infection, tumours, surgeries, or any other cause of scarring may lead to urethral narrowing or stricture. Mechanical narrowing of the urethra without scar formation for example, developmental causes, cancer or prostate enlargement, can also cause urethral stricture.

is urethral stricture is significantly more common in men and boys compared to women and girls. Indeed, the condition is considered to be rare in females. According to one study, about one-half of causes of urethral stricture are from medical procedures and manipulation of the urethra or nearby structures (surgeries, catheter insertion, etc.).

Symptoms of urethral stricture can range from no symptoms at all (asymptomatic), to mild discomfort, to complete urinary retention (inability to urinate) and include: difficulty starting urine flow, painful urination (dysuria), incomplete emptying of bladder, urinary incontinence.

Some of the possible symptoms and complications of urethral stricture include: decreased urine stream, blood in the urine (hematuria), discharge from the urethra and pelvic pain. Whilst medical history, physical examination and symptoms can be suggestive of urethral stricture, additional dEagnostic tests may be helpful in further evaluation.

Urinalysis (UA), urine culture, and urethral culture for sexually transmitted diseases (gonorrhoea, chlamydia) are some of the typical tests that may be performed. Examination of the prostate and screening for prostate cancer (manual exam and measurement of prostate specific antigen or PSA) may also be performed by a doctor. Oftentimes, imaging and endoscopic studies are necessary to confirm the diagnosis and identify the cause of urethral strictures.

An embodiment of a catheter 20 according to a first aspect of the invention is shown in Figure 2 in position, in a first un-inflated state, S within a urethra 22 of a penis 24 in a human male patient. Distal end 26 of the catheter defines an inlet through which urine may pass from bladder 28. The catheter is a two lumen catheter, comprising an elongate lumen, which extends along the complete length of the catheter, with a second lumen defining, for a length determined by the function of the catheter, a inflatable section and an associated feed section which does not inflate or expand to any substantial degree. In a first application, the inflatable section 32, or balloon section, having a length of approximately 20mm is positioned within the urinary sphincter region of the urethra.

The inflatable section of the catheter can then be inflated by a fluid so as to increase the diameter of the catheter by way of pump 29, connected to a proximal end portion of the catheter, to which it is connected via tubes defined within the walls of the urethra (not shown in this figure). The continuous inside passage or internal conduit of the catheter defines a flow path through which urine may pass, via a faucet or similar, into a liquid receptacle, commonly known as a catheter bag 33 or be otherwise directed. The tube is formed of a suitable flexible elastic material, such as silicone, capable of being disinfected and suitable for medical use.

In use, upon insertion through the sphincter, the inflatable portion is inflated whereby the health care worker or patient, as the case may be, can then increase the circumference in the area where the sphincter is located. The pump 29 also has a valve (not shown) which enables deflation of the inflatable section or bladder 32. This type of catheter will have an initial cErcumference of 4 -8mm with models having larger circumferences to suits the patient's initial condition and allow an inflation of up to 15 -25mm. Conveniently, a nominal circumference will be printed, otherwise marked or colour coded with regard to their initial size and a maximum inflated circumference.

Referring now to Figure 3, an embodiment comprises a two lumen tube with an insertion length short of 330mm and a total length of approximately 400 mm. The distal end of the device incorporates a dilation inflatable section 1 capable of inflation up to 8 mm in diameter and 40 mm in length. The length of the dilation inflatable section is selected so that it corresponds that it extends in length beyond the stricture; for example a prostate gland will be up to 60mm around the base of the bladder; the inflatable section will then be selected so that it is mm in length and positioned toward the distal end of the catheter, the mm inflatable section shown in Fig 1 is a known dilation inflatable section size readily available in stent applications in blood vessels.

The proximal end of the device has a luer lock connection 2. This allows connection with a syringe (not shown) of saline solution for inflating the inflatable section. The other tube or lumen allows urine to drain from the bladder through the open end of the tube 3. This tube can simply be directed into the toilet by the patient. There may be a requirement to provide a rinse of the bladder, in which case a third lumen may be provided, along with a luer lock or other appropriate fastening or container to enable connection with an appropriate fluid supply and the like.

Figure 3a shows an alternative catheter, where an inflatable section is arranged substantially along the whole length of the urethra, whereby to facilitate ease of urination for those who suffer other conditions, such as gonorrhoea, where substantially the whole of the urethra is subject to disease and inflammation. In this instance, a stainless steel braid or other suitable material may be provided as shown in Fire 3b; the feature of multi-lumen tubing is known in the art.

Other features of the present invention provide a catheter with a surface coating that will ease its insertion through the urethra and into the bladder and additionally or alternatively will also contain anti bacterial agents in order to reduce the chance of an infection being introduced in to the bladder. Such lubricants may also assist in regeneration of the lining of the urethra, conveniently to reduce scarring. A duct can be incorporated into the structure of the catheter during manufacture, to allow urine held within the bladder to flow out once the sphincter has been breached. A preferred variant will have an axially ribbed external configuration so that, in use, a gentle micro-scuffing of the sphincter contact surface, can be provided upon axial movement of the catheter in a back and forth motion, and act to discourage further scar tissue growth.

In the alternative, the ribs may be configured in a screw-like fashion, whereby an alternative gentle micro-scuffing action can be generated by the user rotating the catheter using the proximal portion of the catheter as a handle. The present invention also provides an opportunity for reducing a frequency of use of the device and thus reduces the risk of bladder infections occurring, since catheter retaining means as presently employed by in-dwelling catheters within the bladder provide an infection bridge thereto.

The inflatable section will be positioned, in use, so that it is adjacent any stricture -indeed, it shall typically be sized so that it extends beyond any stricture by a small distance, whereby to ensure that the inflatable section is effective and that positioning need not be overly exact; the insertion of a device can be painful and so manipulation backwards and forwards is not welcomed in practice.

Figure 4a and 4b show how a distal end of a catheter 20 may be expanded from, for example, a 6 mm circumference to a 13 mm circumference. In use, fluid, preferably an incompressible fluid, is urged from a pump (not shown in this figure) along pipe 42 defined within the wall 44 of the catheter 20 to increase the size of inflatable section 32.

The present invention can conveniently be configured to have the following dimensions, for humans, using known materials for catheters: Type Nominal catheter length Male 30 to 35 cm excluding handle I drain exit Female 15 to 20 cm excluding handle I drain exit Juvenile 10 to 30 cm excluding handle I drain exit The design can be manufactured in a number of sizes -for human use, the normal range of diameters extends from CH8 to CH 12 (or F8 to Hi).

Smaller versions can be provided for veterinary use and for narrow strictures in humans; larger ones for equine use -diameters of up to CH38 and lengths of 1.Sm being in common use. Concomitant with a reduction in size, there will be a reduction in stiffness, which shall affect efficiency of drainage to a degree. The dilation section is capable of being inflated up to a maximum diameter of CH24 (8mm) for nominal CH8 -CH12 sizes; greater inflatable section sizes are determined for other larger French diameters. The inflatable section itself can vary in volume, typically, from 5 cc to 30 cc, depending on the required application.

By the provision of catheters in a range of overlapping sizes, a treatment program can be followed to enable treatment program to correspond with a desired enlargement of the sphincter over time, whereby to provide the optimum flow of urine depending upon their own physical bladder characteristics, after a treatment period. It will be appreciated that a healthcare worker can monitor progress of the enlargement and provide appropriate advice; a desired flow may, for example, not be achievable because of previous scarring or other tissue damage. It will be appreciated that by increasing the opening range of the sphincter, it will enable a reduction of the muscle stress required to expel urine from the bladder. A problem that is known with scar tissue, growth in the scar tissue can still occur up to a year from an originating procedure or event which affected the sphincter or other part of the urethra which has become restricted through disease, injury etc..

It is also known, in some cases, that there is a urethral bypass; a catheter enables emptying of the bladder, which catheter has a pathway to outside the body through might be directly fed through a bladder wall and exhausted via a pubic abdominal section, whilst a blocking urethral stricture is present. During this period of time, a user of the present invention may use a reduced diameter catheter whilst the urethra is not in service and gently increase the dimensions, over a period of time, with a gradual increase of the outside diameters of the inflatable section due to partial inflation in the first instance and then use by a catheter of an increasing diameter. The present invention can be provided with sizes of un-inflated catheter as small as 1mm in diameter (CH3); upon inflation the diameter can double or treble.

The inflation catheter design of the present invention can provide a patient having problems with their urinary sphincter, or a stricture giving rise to a catheter flow problem, with a device that will assist in increasing urinary flow in patients having such conditions. Whilst the use of the S device is intended to significantly increase the duration between corrective surgical procedures and potentially remove the need for further interventions, it is likely to be used to prevent such invasive procedures if a sphincter or poor flow problem is diagnosed before a blockage has occurred. Whilst the embodiment described above is a male device, the catheter can be formed of a length for use by both sexes with male and female versions as well as units for juveniles. The device would be provided with user instructions and individually packaged in a degradable material once opened. A source of compressed fluid would be provided to allow expansion of the catheter in the required zone. Conveniently this fluid comprises a saline solution, although other fluids are known. The catheter is conveniently marked with the initial entry size and the fully expanded size that can be achieved on each unit. The range of units will be arranged to allow larger entry sizes to be used where possible, but the full expansion size would be less. This arrangement is aimed at helping patients to open restricted entry sphincters while offering other units that will maintain a free flow and discourage scar tissue to grow once the sphincter has been stretched. A product range may include a selection of catheters with a number of differing sizes of outside diameter In detail, the catheter is conveniently formed from polyurethane, Teflon, silicone or latex; other materials such as PET, polyvinyl chloride (PVC) or nylon can be employed. Due to silicone's non-irritating properties, silicone catheters have been found to be suitable for medium to long term placement. These catheters vary in length; the longer ones are typically used for males and the shorter ones for females. Further, silicone catheters are reusable and autoclavable.

The catheter is hollow throughout with the distal end preferably comprising a form of stilet to provide a degree of stiffness in a pliable material. The end is not sharp -since one does not wish to cause injury upon insertion, as is known. It is frequently recommended to use a PTFE coated wire guide, which are available with a guidewire introducer or peel away introducer. Indeed, the stilet may also follow the form of a "sharks mouth", also as is known and as shown in Figure 4c. Additionally, through-holes or perforations in the stilet may be provided to ensure as complete drainage as possible, in use and in position at the base of the bladder of a patient, as shown in Figure 4d. Indeed, by not, therefore, depending on a single orifice at the point, which may be blocked by mucus, blood, or other products of disease, drainage can be ensured.

Whilst for many conditions a disposable catheter is appropriate, an indwelling -long-term (three -four weeks) or short term (one -several days) may also be appropriate. It is the practice in certain care institutions, to provide elderly patients with catheters upon entry to a hospital or care-home, for convenience and to dispense with the requirement of bed pans and the like. Catheters fixed by a physician or health care worker have a retaining means such as flaps or a balloon that sit in the bladder holding the catheter in place. Since the sphincter cannot shut properly with catheter in place this will give rise to the possibility of infection entering the bladder. The presence of an in-dwelling catheter for a long period can result in prolongation of a stay in the care-home or hospital due to complications with a catheter. This type of infection is very common and difficult to overcome with the known systems. The present invention, once in place, can be inflated to allow the urine to flow and can be removed once the bladder has been emptied. The present invention therefore provides a disposable alternative or a short-term catheter which, by gripping a portion of the urethra, enables balder control to be performed without the placement of anchors within the bladder, which can introduce pathogens to the bladder, and/or initiate a decrease in bladder control though having a long-term placement of a catheter and degeneration of the sphincter control.

As discussed above, the circumference of the catheter in accordance with the present invention is smaller than catheters currently available so that it can easily enter regions of partial occlusion of the urethra as defined by the sphincter or other occlusion. Accordingly, for example, the catheter has a better chance of entering a reduced diameter sphincter that normally would not permit the passage of currently available devices.

Present catheters are of a fixed size; if the fixed size is not able to pass the obstruction, then a catheter has to be fitted under anaesthetic. The user is able to carry out this process, following diagnosis and simple instruction regarding the placement of the present invention.

It will also be appreciated, particularly for indwelling applications, that a multi-lumen catheter may provide further conduits for thermal, optics, and various medical devices. The present invention can allow selective access via a lumen to a disease site, for example within the bladder.

It is known that the ejaculatory ducts are situated in the region of the prostate, between the two sphincters. Where a stricture of the lower sphincter or other part of the urethra prevents passage of sperm from the ejaculatory ducts, the invention can provide a further benefit. By the provision of an inflatable section to be placed adjacent the primary sphincter, at the base of the bladder, net-like walls which are placed proximate the ejaculatory ducts, then when the inflatable chamber is inflated, sperm would be provided with access past the lower sphincter or other striction.

Antimicrobial catheters are coated on both internal and external surfaces with silver sulfadiazine, heparin and the like for the immune suppressed patient. Silver Sulfadiazine coating provides a precautionary protective enhancement. Further, pharmacologic management of diseases typically affecting the bladder frequently require drug administration by way of a catheter into the bladder. Drug delivery by this route, referred to as intravesical delivery, allows drug delivery at the desired site with reduced systemic side effects compared with oral delivery systems. These characteristics ensure maximal therapeutic benefit to occur at the desired site and provide genuine benefits for patients who have morbid adverse effects from oral administration. Bladder cancer, cystitis, and neurogenic bladder are the common conditions managed by this form of drug administration. Accordingly, the present invention can utilise the central lumen for drug delivery, or more preferably comprise a further lumen for the delivery of drugs, the further lumen having an appropriate luer lock or similar whereby to enable intravesical delivery of a drug.

Intravesical delivery of bacillus CalmetteGue rin (6CC) is considered first-line treatment for superficial bladder cancer, and in most patients, the complete response rate from 5CC is slightly higher for carcinoma in situ than for papillary tumours. The intravesical route is not the predominant route for other ailments of the bladder, but nearly half of overactive bladder patients cannot tolerate oral administration of anti-cholinergic agents because of troublesome side effects such as excessive dry mouth, constipation, or blurred vision. The systemic side effects of the most widely used anti-cholinergic (oxybutynin) are believed to be caused by the high plasma level of its active metabolite. Delivery of the anti-cholinergic agent directly into the bladder in such patients can bring about a local anti-cholinergic effect, with improved drug tolerability and patient compliance.

Further, in accordance with another aspect of the present invention hydrophobic polymers having water-liable linkages connecting monomers that are fortified with the incorporation of ester or imide bonds. Examples of such polymers include polyanhydrides and polyorthoesters. Additionally, by employing such polymers in catheter applications, a single device can be called upon to provide the necessary support to a body lumen and simultaneously dispense a pharmacological agent in a controlled manner.

Drugs such as for example heparin or other proteins can readily be added to the reactants before or during the polymerization process.

Alternatively, some drugs may be infused throughout the polymer after polymerization is completed. If desired, the drug may be applied to the surface of the cured polymer to cause the entire dosage to be released shortly after implantation.

The first step in the manufacture of a catheter is the production of the long, thin tube that will be inserted into the bladder. InitFally, lEquid rubber silicone is poured into a mould at room temperature to enable vulcanization. The mould is shaped like the desired catheter with either two or three outputs. The silicone is then heat cured. This procedure can take anywhere from 0.5 to 40 hours. Once cooled, the tube is withdrawn from the mould. A small opening is then punched in the distal end of the tube furthest away from the two outputs. A thin band of cured latex is slipped over the tube by hand to form a sheath around the tube. It is positioned so that the latex covers the opening that has been punched in the tube.

To form the inflatable section, the entire length of the tube is dipped in S latex, which creates an overcoat layer and bonds the band to the tube proximate to the distal and proximal ends of the band, forming the inflatable section. This adds to the thickness of the inflatable section and is used to adjust the outer diameter of the tube to the desired size. The inflatable section may be ribbed to assist in even inflation; additionally, the inflatable section may be provided with a wire braiding which limits a maximum diameter that can be attained. The catheter is then suitable for assembly with other components including the inflatable section fluid syringe or similar -the inflatable section can either be filled with sterile water or air -and attached to a syringe. The catheter can also be attached to a drainage bag, if required.

Claims (1)

1. <claim-text>Claims 1 A catheter comprising a length of plastics tube having a distal end, for insertion into the urethra, and a proximal end, wherein an inflatable section is defined within the walls of the catheter and is positioned along the length of the catheter, the inflatable section communicating to the proximal end of the catheter via an internal conduit, the conduit terminating in an adaptor for attachment to a fluid pump, wherein in use and operably positioned within a urethra, the inflatable section can be inflated whereby to increase the diameter of the inflatable section of the catheter from an un-inflated state to an inflated state.</claim-text> <claim-text>2 A catheter according to claim 1, wherein the inflatable section is positioned a distance of 20 -50 mm from the distal end.</claim-text> <claim-text>3 A catheter according to claim br 2, wherein the inflatable section has a length of between 10 -80 mm.</claim-text> <claim-text>4 A catheter according to claim 1, wherein the inflatable section extends substantially along the length of the catheter.</claim-text> <claim-text>A catheter according to any one of claims 1 -4, wherein the un-inflated diameter of the bladder portion of the catheter is in the range of 4 -8mm.</claim-text> <claim-text>6 A catheter according to any one of claims 1 -4, wherein the inflated diameter of the bladder portion of the catheter is in the range of 15 -25mm.</claim-text> <claim-text>7 A catheter according to any one of claims 1 -6, wherein the bladder section defines an external axially ribbed configuration.</claim-text> <claim-text>8 A catheter according to any one of claims 1 -7, wherein the inflatable section is reinforced whereby to inflate substantially uniformly along the length of the inflatable section.</claim-text> <claim-text>9 A catheter according to any one of claims 1 -6, wherein the bladder section defines an external screw-like ribbed configuration.</claim-text> <claim-text>A catheter according to any one of claims 1 -9, wherein the inflatable section is reinforced by braiding.</claim-text> <claim-text>11 A catheter according to any one of claims 1 -10, further including a second or further inflatable section.</claim-text> <claim-text>12 A catheter according to any one of claims 1 -11, wherein the adapter at the proximal end of the catheter is connectable with a fluid pump.</claim-text> <claim-text>13 A catheter according to claim 12, wherein the fluid is one of water, a saline solution, air, gaseous oxygen, gaseous nitrogen or a mineral oil.</claim-text> <claim-text>14 A catheter according to any one of claims 1 -13, further comprising an axial fluid passage for drainage of urine.</claim-text> <claim-text>A catheter according to any one of claims 1 -13, further comprising a further lumen to enable flushing of the bladder, provision of localised medication, inspection and diagnosis, and surgery.</claim-text> <claim-text>16 A set of catheters according to any one of claims 1 -13, the set of catheters comprising a number of diameters, whereby to provide a number of catheters for progressive use as a stricture becomes increasingly dilated.</claim-text> <claim-text>17 A catheter according to any one of claims 1 -16, wherein the outside surface of the catheter is provided with one or more of a medication, lubricant or other coating, whereby to enable topical application of a medication, to facilitate insertion or otherwise.</claim-text> <claim-text>18 A catheter according to claim 17, wherein the catheter comprises polymers wherein the degradation rate of a polymer matrix is faster than the rate of water penetration into the interior of the polymeric mass.</claim-text> <claim-text>19 A catheter according to claim 18, wherein the material employed in coating a catheter includes hydrophobic polymers having water-liable linkages connecting the monomers that are fortified with the incorporation of ester or imide bonds, such as polyanhyd rides and polyorthoesters.</claim-text>