WO2003073950A1 - Optical fibre catheter for thermal ablation - Google Patents

Abstract

This invention concerns an optical fibre catheter for thermal ablation by laser rays. It comprises optical fibres (12) with a proximal end connectable to a laser radiation source unit, a distal end and encompassed by a peripheral sheath (16). The distal ends of the optical fibres (12) are truncated at a slant forming an oblique end part (19) for each of them. The oblique end parts (19) are associated with a nearby reflecting surface (20) enclosed by a metal point (21) at the distal end of the catheter, so that the laser rays travelling along the optical fibres are reflected laterally towards the outside, for thermal ablation around the catheter. The optical fibres are enclosed in a blocking ring near the oblique ends.

Description

" OPTICAL FIBRE CATHETER FOR THERMAL ABLATION"

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Field of the Invention

This invention concerns optical fibre catheters in general for medical and surgical use, and refers in particular to an optical fibre catheter for thermal ablation using laser. Prior Art

Well known among the devices available at present in the field of medical and surgical devices are also catheters for performing thermal ablation in various parts or organs of the body reached by passing though ducts or natural vessels. Also well known among these catheters are those comprising optical fibres for thermal ablation using laser rays. The optical fibres in these catheters extend, depending on the length of the catheter, from a proximal connector connectable to a laser unit as far as the distal end where the optical fibres protrude to irradiate the part to be treated.

However, in a form such as this, the required irradiation takes place through the free ends of the optical fibres and in essence it is directed only forwards, frontward of the distal part of the catheter. Some thermal ablation operations using laser rays may however require in particular radial irradiation, like a circular crown around the catheter, an action which present well known catheters are unable to perform. Objects and Summary of the invention

The aim of this invention is to provide a remedy for this shortcoming. Its main objective is in fact to provide a catheter with a particular innovative combination of functional elements which primarily enable radial irradiation for thermal ablation treatment to be carried out around the catheter. A further object of the invention is to provide a catheter capable of accepting at least one additional optical fibre for front thermal laser irradiation ablation, also.

These objects and the inherent advantages stemming from them are achieved by an optical fibre catheter connectable to a laser source unit, wherein the distal ends of the optical fibres are truncated obliquely and associated in addition with an arch shaped reflecting surface metal point placed on the distal end of the catheter, so that the laser rays flowing along the optical fibres are reflected laterally towards the outside of the catheter itself.

The catheter can also house a longitudinal duct. When present, this duct can possibly be used for inserting and moving a guide wire or for housing at least one additional optical fibre also for irradiating immediately in front of the catheter. Brief Description of the drawings

Greater details of the invention will become more evident in the following description made with reference to the indicative and non- limiting drawings enclosed, in which:

Fig. 1 is a view of the optical fibre catheter;

Fig. 2 is an enlarged of a side view of the distal part of the catheter in Fig.1 ;

Fig. 3 is further enlarged longitudinal section view of the distal part of the catheter shown in Fig.2 Fig. 4 is a cross section view in direction of arrows A -A on Fig. 2 of a four fibre catheter

Fig. 5 is a view of a similar cross section of a six optical fibre

catheter; and

Fig. 6 is a cross section view of the metal point in direction of

arrows B-B in fig. 2

Detailed Description of the invention

The catheter proposed herein comprises of a flexible central

element 1 1 , extending lengthwise along a longitudinal axis, around which

and positioned in parallel are optical fibres 12, the number of which can be

chosen according to requirements. In the examples in Figs. 4 and 5, the

number of optical fibres is four and six, respectively.

The centre element 1 1 can be solid, but tubular is preferable so as

to accommodate a longitudinal duct 13.

The optical fibres 12 extend from a proximal end 14 almost

reaching the last part of a distal end 15 of the centre element 1 1. They

are enclosed in a flexible housing sheath 16 and can be held in position by

a filler or bonding agent, such as a resin, inserted between the sheath and

the fibres themselves.

At the proximal end 14, the optical fibres 12 can be connected by

means of a connector 17 to a laser radiation generating unit - not shown.

The optical fibres 12 are encompassed by a blocking ring 18 in close proximity to their distal part 15; such ring, for example, may be made

of platinum or gold or however of a material suitable and compatible with

the destination and use the catheter is put to. The optical fibres 12, in their distal part 15, that is in the section beyond the blocking ring 18, have a portion exposed towards the outside and are cut at a slant so as to finish in an oblique terminal 19. As shown in Fig. 3, the oblique end part 19 of each optical fibre is slanting from the outside towards the axis of the centre element and associated with a nearby reflecting surface 20 which is also slanting. This reflecting surface 20 is formed by a metal ogival or similar shaped point 21, attached to the distal end of the central element 11. In this way, the laser rays which travel along the optical fibres 12 are reflected and emitted laterally towards the external of the catheter, at the distal end of the latter, around it, irradiating the surrounding part to be treated by thermal ablation.

The slant angle of the oblique end part 19 of each optical fibre 12 and the same applying to reflecting surface 20 can be chosen as required on the basis of the total or partial reflection needed. This slant angle can be the same for all the optical fibres of the same catheter or can vary in the case of some optical fibres compared to the others, in this way the emission field of the laser rays can be oriented differently according to the requirements for irradiation of the part needing treatment.

When the catheter has a longitudinal duct 13, this can be used to receive a guide wire or also for housing an additional optical fibre, nor shown here, with its own end piece at the front of the metal point in order to meet irradiation needs, where required, also in front of the catheter for front thermal ablation.

Claims

OPTICAL FIBRE CATHETER FOR THERMAL ABLATION"

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C L A I M S 1. An optical fibre catheter for thermal ablation using laser, comprising a central flexible longitudinal element (11 ) and a number of optical fibres (12), running externally along the central element between a proximal end connectable to a laser ray source unit and a distal end, and enclosed in a peripheral sheath (16) with the possible insertion of a filler or bonding agent, characterized in that the distal ends of the optical fibres (12) are truncated at a slant forming an oblique end part (19) for each one, and in that the oblique ends of the optical fibres are associated with a nearby reflecting surface (20) enclosed by a metal point (21 ) at the distal end of the catheter, so that the laser rays running along the optical fibres are reflected sideways towards the external of the catheter.

2. The optical fibre catheter according to claim 1 , wherein the oblique end part (19) of the optical fibres (12) slants from the outside towards the centre of the central element (11 ) sloping backwards towards the back end of the catheter and is associated with the reflecting surface (20) sloping in the same way, the slant angle of said oblique end part and the reflecting surface being chosen according to the total or partial reflection of the laser rays.

3. The optical fibre catheter according to claims 1 and 2, wherein the slant angle of the oblique end part (19) is the same for all the optical fibres.

4. The optical fibre catheter according to claims 1 and 2, wherein the slant angle of the oblique end part is different in some optical fibres from the others.

5. The optical fibre catheter according to any of the previous claims, wherein the optical fibres (12) are surrounded and blocked by a peripheral ring (18) near their oblique end part (18) leaving only enough room for the emission of the reflected laser rays.

6. The optical fibre catheter according to any of the previous claims, where the metal point (21 ) is ogival shaped and attached to an end section of the longitudinal central element.

7. The optical fibre catheter according to any of the previous claims, wherein the longitudinal central element (11 ) is solid.

8. The optical fibre catheter according to any of the previous claims from 1 to 6, wherein said central element (11 ) encompasses a longitudinal duct (13) either to receive a guide wire or at least one additional optical fibre for front emission from distal end.