GB2478988A

GB2478988A - Flexible endoscope with transverse and longitudinal slots

Info

Publication number: GB2478988A
Application number: GB1005114A
Authority: GB
Inventors: Eyal Peleg
Original assignee: VITAL VIEW Ltd
Current assignee: VITAL VIEW Ltd
Priority date: 2010-03-25
Filing date: 2010-03-25
Publication date: 2011-09-28
Also published as: GB201005114D0

Abstract

A tubular frame member of a catheter or endoscope having an articulating segment 10 provides for bending the frame within at least one deflecting plane. The articulating segment 10 is characterized by spaced apart vertebras 16 symmetrically disposed relative to the axis of the tubular frame member (see figure 5). Transverse slits 14, 14' each have a pair of longitudinal slits 18, 18' disposed at both ends, which separate adjacent vertebras. The spacing disposed between each vertebra provides for conveniently flexing the vertebra relative to the axis of the frame member by inducing plastic deformation onto the axial shafts 20 connecting coplanar vertebras. The transverse slots may be wedge shaped (see figure 3) and the longitudinal slots may extend in both axial directions from the transverse slot. Some vertebra may be deformed in order to accommodate a pull wire (see figures 6, 10). The longitudinal slits may be offset to provide for flexing in more than one plane (see figure 7).

Description

BENDABLE CATHETER

FIELD OF THE INVENTION

The present invention relates in general to bendable catheters. In more particular the present invention relates to catheters having a rigid and tubular frame member that has an articulating segment that comprises spaced apart vertebras.

to BACKGROUND OF THE INVENTION

Cutting a plurality of axially aligned slits that are azimuthally extending in an arc partway around the axis of a catheter thereby providing the catheter with laterally bending capability is known. For example in US patent 7,637,903 a catheter having an articulating segment providing for simultaneously bending is the catheter in different planes is disclosed. The articulating segment of the disclosed catheter has one or more sets of pairs of slits. The slits of a pair are diametrically opposed to each other. Successive slits of a set are axially offset.

In a case in which the axial offset of slits of one set is of ninety degrees relative to the slits of the other set, bending the catheter in two perpendicular planes can be accomplished.

It is an object of the present invention to provide tubular frame member having an articulating segment for a catheter. The articulating segment provides for bending the catheter in at least one plane. Furthermore, it is an object of the present invention that the provided tubular frame member is cost effective, simple to implement and convenient to use.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an elevational view of a segment of a tubular frame member of a catheter according to an embodiment of the present invention; Fig. 2 is an isometric view of a segment of an articulating segment of the tubular frame member shown in Fig. 1; Figs 3 is an isometric view of a segment of an articulating segment of a tubular frame member of a catheter according to a preferred embodiment of the present invention; Figs 4 -5 are respectively elevational view and isometric view of a pair 0 of coplanar vertebras of the articulating segment shown in Fig. 3; Fig. 6 is an isometric view of a segment of an articulating segment of a tubular frame member of a catheter according to another preferred embodiment of the present invention; Fig. 7 is an isometric view of a segment of an articulating segment of a tubular frame member of a catheter according to another preferred embodiment of the present invention; Fig. 8 is a scheme of an endoscope having an articulating segment as is shown in Fig. 6; Figs 9 -10 are sectional views of the articulating segment of the endoscope shown in Fig. 8 respectively made across two different planes;

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In accordance with the present invention a tubular frame member of a catheter having an articulating segment is provided. Tubular frame members having articulating segment of the invention are suitable especially for catheters to be introduced into, and propagated through, relatively narrow passageways existing or generated within mammalian bodies. The articulating segments of the invention are especially adapted and arranged to be pre-shaped to assume desired curvatures prior to their introduction into the targeted passageways.

Reference is now made to Figs I -5. In Fig. I a tubular frame member of a catheter according to an embodiment of the present invention is shown. Articulating segment 10 disposed at the distal end of tubular frame member 12 provides for deflecting the distal segment of the frame member considered by deflection angle 13. Deflection angle is measured relative to the axis of tubular frame member 12. A segment of articulating segment 10 is is shown in more details in Fig. 2. Transverse slits 14 each of which extends along an arc partway around the axis. The arc is of the same azimuth angle measured relative to the axis of tubular frame member 12. The transverse slits are successively arranged along one side of articulating segment 10. Slits 14' are symmetrically arranged at the opposite side of articulating segment 10, such that semi circular vertebras such as vertebras 16, or 16' interleave between any pair of successive slits 14, or 14' respectively. Spacing of a predefined width separates between adjacent vertebras 16, or 16'. Longitudinal slits 18, 18' are axially disposed according to the present invention at both ends of each of transverse slits 14 and 14' respectively. The ends of the longitudinal slits extend beyond the margins of the respective transverse slit towards both sides. Successively arranged longitudinal slits 18, with longitudinal slits 18' collectively form axial shafts 20 that are symmetrically disposed at both sides of articulating segment 10. In Fig. 3 a segment of an articulating segment of a tubular frame member of a catheter according to a preferred embodiment of the present invention is shown. Each of the transverse slits gradually gets wider towards both ends of the slit considered. The width of the transverse slit reaches its maximal level at the point in which it is connected to the respective longitudinal slit. The rate by which a spacing generated by a transverse slit get wider, the widths of the transverse slits measured at mid-point, the widths of the vertebras, as well as the dimensions of the longitudinal slits are selected according to the present invention in consideration with the magnitude of the maximal angle by which one circular ring can be inclined relative to its closest neighboring ring. Normally care should be given not to exceed curvature levels that comply with the limits imposed by any member that has to be inserted into, and threaded through, the frame member considered. For example fiber-optic bundle of an endoscope that might be employed, are normally characterized 0 with radii of maximal curvature that directly imply on the level of maximal inclination angle between adjacent rings of the articulating segment considered.

The present invention concerns cases in which bending the distal end of the frame member within a deflecting plane towards both sides of the axis at the same inclination levels can be accomplished. Therefore symmetrical is arrangement of the slits and vertebras and the even distribution of the various dimensions as described above are especially suited for such cases. The main concern of the present invention is catheter having a relatively small diameter of a few millimeters. Following are typical dimensions of the slits and vertebras of an articulating segment such as the one shown in Fig. 3. Such structured and arranged slits and vertebras provide for symmetrically bending the frame member relative to its axis within a selected deflecting plane. (Lengths are measured in units in which one unit length equals the length of the diameter of the frame member considered.) Width of a vertebra 22 ranges between a few tenths to about the full length of the diameter; the length 24 of a longitudinal slit ranges between 0.25 to one full length of a diameter; the width of a transverse slit 26 is of a few hundredths up to about a fifth of the length of a diameter; The full width of a transverse slit measured at the point of maximal width 28 ranges between a number of hundredths to a fifth of a length of a diameter; the width of a longitudinal slit 30 ranges between a few hundredths to a third of a diameter; the width of the axial shaft 32 ranges between a few hundredths to a quarter of the diameter; and the width of the stem 34 ranges between 0.2 to 0.7 of a length of a diameter.

A pair of coplanar and diametrically opposed vertebras forms a circular ring that is connected to both axial shafts. In Figs 4 -5 elevational and isometric views of such ring are respectively shown. Stems 38 respectively connect between both ends of a vertebra and each of the respective segments of the axial shafts. Symmetrical stems 38' provide for connecting vertebra 16' at the opposite sides of axial shafts 20. Azimuth angle 40 spans the full length of a vertebra. Doted line 42 indicates the cross section of the deflecting plane which is perpendicular to the plane of the paper of the referenced drawings and the plane of the circular ring.

An articulating segment such structured and arranged provides for bending the distal end of frame member 12 in one deflecting plane; say the plane of the paper of the referenced drawings. An exemplary cylindrical frame member is made of stainless steel, has a diameter of 1.5 millimeters (mm) and the thickness of its sidewall is about 0.1 mm. Slits having shapes and dimension as described above with reference to Fig.3 are structured and arranged to form such articulating segment. Cutting the slits can be accomplished as known, preferable is laser cuffing that enables the various shapes and margins of the slits as described herein at affordable costs quite easily. One may manually twist and deform by plastic deformation the respective segments of the axial shafts and the stems of the articulating segment of this exemplary frame member by means of one's fingers and bend the articulating segment laterally with respect to the axis of the tubular member within the deflecting plane. The inventor of the present invention, has further experienced that in cases in which the frame member is enclosed, or is not enclosed, within a tubular sheath made of polyethylene, or other flexible material such as the materials that are normally utilized for manufacturing cannulas and/or catheters for medical use, such bending that is involved with partially deform ing the articulating segment can be easily accomplished.

Furthermore, pulling such partially deformed and deflected frame member off the sheath is involved with its being straightened up back into its original cylindrical form. The plastic deformation that causes the straightening of the articulating segment is effected by strains exerted unto the deflected articulating segment by the twisted sidewall of the flexible sheath while the bended segment of the frame member is released and gets off the sheath.

Alternatively, pull wire can be used to deflect and/or straighten up the distal end of the tubular frame member. Pull wires are attached to the outermost distal vertebras as known. Each pull wire is threaded across a vertebra its wall is pressed below the span of the radius of the frame member.

First, the wall of every, say forth vertebra 50 disposed along segment 52, shown in Fig. 6, is inwardly bended. Such bending results in apertures disposed at both sides of vertebra 50 that are opened into the lumen of the io frame member considered. These apertures provide for threading pull wire 54 through. The number of vertebras 56 that are not such deformed need not be four but can be any selected number as desired.

Reference is now made to Fig. 7 in which a segment of an articulating segment of a tubular frame member of a catheter according to another is preferred embodiment of the present invention is shown. Articulating segment includes two sets of pairs of vertebras as described hereinabove. The first set designated by 62 consists of batches of vertebras grouped together in coplanar pairs each of which includes two vertebras symmetrically disposed at two opposing sides of the axis of the frame member considered. All the vertebras disposed at the same side of the axis span the same azimuthal range and each of its endpoints has the same azimuth angle. The other set designated by 64, consists of similarly grouped vertebras except that their endpoints are axially offset by a predefined angle. Therefore this articulating segment provides for deflecting the distal end of this tubular frame member in two planes that intersect each other at this predefined angle.

EXAMPLE 1

Tubular frame member having an articulating segment of the invention can be incorporated into endoscopes, especially suited to be introduced into relatively narrow passageways within mammalian bodies.

Reference is now made to Figs 8 -10. In Fig. 8 endoscope 70 having a tubular frame member including articulating segment of the invention is shown. Tubular frame member 72 is cylindrically shaped. Tubular frame member 72 has a diameter of 1.5 mm and the thickness of its wall that is made of stainless steel is 0.1 mm. Articulating segment of the invention 74 disposed at the distal end of tubular frame member 72 provides for deflecting its distal end within at least one plane. Lever 76 provides for selectively moving pull wires through tubular frame member 72 thereby deflecting and straightening the distal end within at least a single plane. Eyepiece 78 provides for viewing images received and o delivered by means of imaging fiber bundle, not shown, that is threaded through the tubular frame member. Connector 80 provides for connecting illuminating source an illuminating fiber bundle, not shown, for illuminate the region distally disposed relative to the distal end of the tubular frame member.

Gas inlet 82 provides for delivering oxygen, or air enriched with oxygen into the lumen of the tubular frame member. Connector 84 provides for fluid connecting gas inlet 82 to sources of insufflating gases.

In Figs 9 -10 sectional views made across planes AA and BB shown in Fig. 8 are shown. Plane AA separates between two rings that are not deformed for threading the pull wires across their surfaces. Plane BB is positioned adjacent to a ring that is deformed for threading the pull wires off and into the lumen of the tubular frame member. Distal end of tubular frame member 90 has sidewall 91 that encloses imaging fiber optic bundle 92, illuminating fiber bundle 94, and pull wires 96. The deformed ring 98 encloses both fiber optics bundles whereas the pull wires are disposed exterior to the volume enclosed by sidewall 99.

A similar endoscope is suitable for insufflating premature babies especially in cases in which insufflating is accomplished even along the process of introducing the tubus into the airways of the baby. The tubular frame member of the endoscope has a diameter that does not exceed the inner diameter of the tubus considered. The frame member of the endoscope is provided with articulating segment of one deflecting plane. First the tubular frame member is inserted into the tubus which is made of flexible material. Shaping the distal

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segment of the endoscope such that it will comply with the curvatures along the airways of the baby is manually accomplished by means of the fingers of the care providing personnel member prior to the insertion of the tubus. There is no need for special channel that is dedicated for delivering an insufflating gas through the endoscope considered. Therefore the width of the frame member can be minimized such that it is suited for introduction through relatively narrow passageways, such as the trachea of a premature baby. The spacing that exists between the electro-optical bundles, the pull wires and the inner surface of the tubular frame member provides for fluid connection that is sufficient for io delivering the insufflating gases.

EXAMPLE 2

Endoscope such as described in EXAMPLE I above can be is employed for guiding standard embryo insertion catheter to enter the patient's Uterus. First the frame member of the endoscope is introduced into a sheath the lumen of which is adapted and arranged for guiding standard embryo insertion catheter. The inlet for insufflating gas of the endoscope is connected to a source of air enriched with CO2 gas, at the same concentration typically utilized for an ambient atmosphere of incubators. Common Hystero -insufflator connected to balloons respectively containing CO2 and sterilized air and a gas blender can be employed for implementing such source as known. Then the articulating segment of the endoscope is pre-shaped to have the suitable curvatures. The insufflating with air enriched with CO2 is carried out along the 2S process of introducing the sheath into the uterus. Such insufflating provides for opening passageway through the cervix, through which the sheath enclosing the endoscope is propagated. Care must be taken not to exceed the pressure of the insufflating gas such that air is not permitted to get into the blood circulation of the patient as known. The introduction process continues until the tip of the endoscope reaches the exact location within the uterus in which the embryo has to be placed. When the desired location has been reached the endoscope is pulled off and is substituted with the embryo insertion catheter. A relatively stiff proximal segment of the sheath provides for straightening up the bended end of the frame member while is pulled off the sheath.

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