This Invention Relates To Urinary Catheters

Urinary catheters are used to assist or control the flow of urine from the bladder of a patient. When a patient needs to use a catheter for an extended period of time, they may use an indwelling urinary catheter. An indwelling urinary catheter has a tube which is introduced through the patient's urethra or directly via an abdominal incision (supra-pubic catheter). Once the distal tip of the catheter is in the bladder it is retained in position by means such as a balloon inflated within the bladder. A lumen extending through the catheter can then drain urine from the bladder.

A common design of indwelling urinary catheter is the Foley catheter. In the Foley catheter, the balloon is toroidal in shape and is located proximally of the catheter tip. A drainage opening which communicates with the lumen is located between the catheter tip and the balloon. Catheters of this design suffer from a number of problems. The tip of the catheter is exposed and can irritate the bladder wall. Material of the bladder wall can become drawn into the drainage opening, causing discomfort and mucosal damage. The drainage opening is spaced from the base of the bladder by the balloon, which prevents the bladder draining completely leading to a residual pool of urine that can become infected.

WO 2015/028786 discloses one approach to addressing at least some of these problems. It provides a urinary catheter having an inflatable balloon which extends over the tip of the catheter. WO 2007/005734 discloses another design of urinary catheter, in which the drainage opening extends proximally of the inflatable balloon.

There is a need for an improved design of urinary catheter.

According to one aspect of the present invention there is provided a catheter comprising: a shaft having a proximal end and a distal end, the distal end terminating in a tip; a drainage opening located at the distal end of the shaft, the drainage opening communicating with a drainage lumen of the shaft; a balloon located at the distal end of the shaft, the balloon comprising a first region secured to the shaft, a second region secured to the shaft and an elastic-walled and/or flexible-walled conduit extending between the first region and the second region, the elastic-walled conduit extending over the tip.

At least part of the first region may be located proximally of the drainage opening. At least part of the second region may be located proximally of the drainage opening.

At least a part of the balloon is in the form of an elongate tube. That part may comprise the elastic- and/or flexible-walled conduit.

The first region may be at one end of the tube and the second region may be at the other end of the tube.

The catheter may be such that: the balloon is in its uninflated state; the tube has lateral edges; the balloon comprises an outer layer defining the exterior of the balloon in its uninflated state; and the balloon is folded so that the lateral edges are located between the outer layer and the shaft of the catheter. In a state of the catheter prior to inflation and/or use, lateral edges of the conduit may be sandwiched between a central portion of the conduit and the shaft of the catheter, for example between the central portion of the conduit and a part of the catheter shaft that is any one or more of (i) a distal part of the shaft of the catheter, (ii) the tip of the catheter, and (iii) a lateral portion of the shaft of the catheter.

The first and second regions may overlap.

The first region and/or the second region may span an arc of greater than 90 degrees around the longitudinal axis of the catheter.

The first region and/or the second region may span an arc of greater than 180 degrees around the longitudinal axis of the catheter.

The catheter may comprise an inflation opening located at the distal end of the shaft. The inflation opening may communicate with an inflation lumen of the shaft and with the interior of the balloon.

The balloon may comprise two walls where it extends over the tip. The region between the walls may communicate with the inflation opening. There may be additional layers of elastic or inelastic material externally of the balloon.

The balloon may be configured such that when inflated an exterior wall of the balloon is located distally of and spaced from the tip of the catheter.

The balloon may be configured such that when inflated an interior wall of the balloon bears against the tip of the catheter.

The drainage opening may be located on a side of the catheter shaft. The balloon may be configured such that, when it is inflated, regions of the exterior of the balloon are located laterally outward of that side of the catheter shaft on either side of the drainage opening.

The balloon may be configured such that, when it is inflated, regions of the exterior of the balloon are located radially outward of the catheter shaft proximally of the most proximal part of the drainage opening.

The balloon may be configured such that, when it is inflated, regions of the exterior of the balloon extend radially outward with respect to the longitudinal axis of the catheter shaft around the majority of the or each drainage opening.

The balloon may be formed of a material that has a tendency to adhere to itself.

The ratio of (i) the mean diameter of the catheter shaft immediately distal of the drainage opening to (ii) the distance from the most distal part of the first region to the tip of the catheter may be in the range from 0.8:1 to 3:1 alternatively from 1:1 to 2.5:1, alternatively from 1.2:1 to 2:1, alternatively from 1:2 to 2:1.

The material forming the wall of the balloon may be of uniform elasticity across its area, or of non-uniform elasticity across its area. The wall of the balloon may comprise one or more thickened regions such as ribs for reducing the elasticity of the wall adjacent thereto.

The balloon may be secured to the shaft at the first and second regions by a mechanical fixing clamping the balloon to the shaft. The mechanical fixing may, for example, be a collar surrounding the shaft. The balloon may in addition be attached to the shaft by adhesive.

The balloon may be configured so that when the balloon is inflated, a wall of the balloon facing the tip is spaced from the tip. The drainage opening may open distally from the tip.

When the balloon is in its uninflated state, material of the balloon may be stowed in the drainage lumen.

According to a second aspect of the present invention there is provided a method for manufacturing a catheter comprising: providing a shaft having a proximal end and a distal end, the distal end terminating in a tip, a drainage opening located at the distal end of the shaft, the drainage opening communicating with a drainage lumen of the shaft and an inflation opening located at the distal end of the shaft, the inflation opening communicating with an inflation lumen of the shaft; providing an elastic-walled conduit having an access opening to the interior thereof; securing a wall of the conduit to the shaft around the inflation opening; introducing a tool through the access opening; piercing the wall of the conduit with the tool at the location of the inflation opening; and closing the access opening.

The method may further comprise: locating the elastic-walled conduit over the tip of the catheter; and securing a wall of the conduit to the shaft on the opposite side of the shaft to the inflation opening.

The conduit may be attached to the shaft of the catheter such that the interior of the of the conduit communicates in a fluid-tight manner with the inflation lumen. The conduit may be fluid-tight except for an aperture to the inflation opening A valve may be located in the inflation lumen. The valve may be capable of resisting flow of fluid from the distal end of the shaft to the proximal end of the shaft.

The catheter may be a urinary catheter. The catheter may be an indwelling urinary catheter.

Parts of the elastic-walled conduit may be inelastic.

The conduit may be located distally of the tip. In an inflated state of the balloon a wall of the conduit immediately distal of the tip may contact or may be spaced from the tip. When the balloon is in an inflated state, the tip may be in contact with material of the balloon or may be exposed.

The conduit may be integral with the first and second regions.

The shaft may be an elongate shaft.

