GB2187390A - Urethral catheter - Google Patents

Abstract

A urethral catheter (10) having a tube (11) encapsulated for a major portion of its length by an outer sheath (14) of inflatable elastomeric material. The sheath (14) is inflatable, so that in use, it can separate the divided walls of a stricture. <IMAGE>

Description

SPECIFICATION Urethral catheter This invention relatesto urethral catheters and particularly to catheters for use after post stricture treatment. Urethral catheters for bladder drainage are well known. A known catheter comprises a tube with an inflatable latableretention balloon at the distal end thereof, the whole being formed from silicone rubber.

An example of such a catheter is an 'All Silicone Foley Catheter' manufactured by Argyle Division of Sherwood Medical.

Urethral strictures may be treated by optical urethrotomy or by dilation with urethral dilators. In some cases it may be necessaryto resort to open surgery (urethroplasty).

Urethral dilation is usually performed with rigid dilators that are passed through the stricture starting with a small diameter dilator and following with progessively large diameter dilators as the stricture is dilated. Such rigid dilatorswould range in size from 10-28 Fr. gauge. The term Fr. gauge stands for French gauge which is otherwise known as Charrier gauge and which relates to the circumference ofthe dilator, catheter, etc. in millimeters e.g. a dilator of 20 Fr.

gauge has a circumference of 20 mm.

Optical urethrotomy is performed using endoscopic equipment with which the stricture can be seen and divided using a sharp blade.

Both techniques have the problem that after the treatmentthe divided walls ofthe stricture mayfall together and heal, so perpetuating the stricture.

The present invention provides a post-urethrotomy catheter which overcomes the aforementioned problem.

According to the invention there is provided a urethral catheter having a tube encapsulated for a major portion of its length in an outer sheath of inflatable elastomeric material.

Preferablytheoutersheath has strengthening ribs therein to prevent herniation of the sheath on inflation. These ribs also have the advantage thatthey help prevent portions of the sheath from sticking to the tube on inflation.

In one embodiment the catheter is nominally 14 Fr.

gauge and is inflatable to 24 Fr. gauge over a length of 22cm. The cather may remain in situ for long periods oftime and is inflated periodically to ensure that the divided wal Is ofthe stricture do notfal I together. The catheter may, for example, be inflated twice per day for a period often minutes; after two to three weeks the divided walls will have epitheliased and the catheter may be removed.

The patient may leave hospital with the catheter in situ and inflate and deflate the catheter himself. This frees the hospital bed for use by another patient. The catheter including inflatable sheath and retention balloon, is made from an elastomericmaterial preferably silicone rubber, butpclyvinyl chloride polyurethane or naturalrubberl#ex maya#o be: used.

Otherfeaturesofthe invention will be apparant from thefollowing description of a preferred embodientshown, by way of example only, in the accompanying schematic drawings in' which :- Figure 1 illustrates a u reth ral catheter according to the invention having an inflatable sheath over a major portion of its length, in the uninflated condition. and Figure 2 illustratesthe urethral catheter Figure 1 with the stricture balloon inflated.

With reference to the drawings there is shown a urethral catheter 10 having a tube portion 11 with a drainage channel therein (not shown) which has an opening 16 atthe distral end ofthe catheterfor drainage ofthe bladderthrough the drainage channel and outlet 17, into a collection bag, in a known manner. The catheter 10 has an inflatable retention balloon 12 atthe distal end thereof. The retention balloon is of a known type and may have a nominal volume of about 5 ml.

An inflation channel forthe balloon 12 extends within the tube 11 and has a connector 13 at the proximal end ofthe catheterfor inflation ofthe balloon by the injection of a known volume of water.

An inflatable outer sheath 14 surrounds the tube 11 for a major portion of its length. For a typical urethral catheterthiscould be for a length between 18-24 cms.

There is an inflation channel for the sheath 14 extending within the tube 11 and which has a connector 15 at the proximal end of the catheterfor inflation of the sheath by injection of a volume of water, nominally 5 ml to achieve the desired expansion.

The catheter is nominally of 14 Fr. gauge and the inflatablesheath 14is inflatable to a nominal 24 Fr.

gauge. In the embodiment shown the sheath 14 extends for a length of between 60%-70% of the length ofthe cathetertube 11 and is preferably of a length of about 22cms. The inflatable sheath 14 is spaced by a distance of about 2 cms. from the retention balloon 12.

The outer sheath 14 may be strengthened by ribs 18.

The ribs can be internal or external ofthe sheath as is desired. These ribs 18 may be circumferential ribs as illustrated in the drawing, but could also be longitudinal ribs (i.e. longitudinal with respectto the tube 11).

The circumferential ribs 18 may be spaced apart by a distance of between 1 to 3 cms as is required to prevent herneation of the sheath. Whilstthe ribs 18 are shown as being equally spaced apart, the distances between the ribs may vary as required.

The catheter as described above is preferably formed from silicone rubber which has a low irritant factor on the urethra, but other materials could be used although these may increase the irritability of the catheter.

In use the urethral stricture is divided by, for example, optical u roth roto my, and the catheterin- serted into the urethra. The retention balloon 12 is inflated in the usual way. The inflatable sheath 14 is inflated periodically to ensurethatthe divided walls of the stricture-do netfail together and this procedure c0ntin#es unt- ii the waits have epitheliasedwhich may take two to three weeks. Afterthe urethra has healed the catheter is removed and discarded.

In the uninflated state, the sheath 14 allows normal urethral secretions to drain around the catheter.

Claims (10)

1. A urethral catheter having a tube encapsulated for a major portion of its length in an outer sheath of inflatable elastomeric material.

2. A urethral catheter as claimed in Claim 1 wherein the said outer sheath has strengthening ribs therein to prevent herneation of the sheath on inflation.

3. Aurethral catheterasclaimed in Claim 2, wherein the outer sheath is strengthened by circumferential ribs.

4. A urethral catheter as claimed in Claim 3 wherein the circumferential ribs are spaced apart by a distance of between 1-3 cms.

5. A urethral catheter as claimed in anyone of Claims 1 to 4wherein the major portion covered bythe inflatable sheath is about60%-70% ofthe length ofthe catheter.

6. Acatheterasclaimed in any one of Claims 1 to 5 wherein said inflatable sheath is inflatable to 24 Fr.

gaugeovera length of between 18-24 cms.

7. Acatheterasclaimed in any one of claims 16 wherein the catheterfurther includes a retention balloon atthedistal end thereof.

8. Acatheteras claimed in Claim 7 whereinthe inflatable sheath is spaced from the retention balloon by a distance of about2 cms.

9. Acatheterasclaimed in any one of Claims 1 to8 wherein the catheter, and sheath, are formed from a silicone rubber.

10. Aurethral catheterasdescribed herein and with referencetothe accompanying drawing.