A CANNULA OF CHANGEABLE LENGTH AND SHAPE

Abstract: A cannula of changing length and shape, built up of spirally wound one or more bands, in which the free unlimited parts of the bands in the cannula wall pass into the interior of the cannula end are freely located along its entire length in guiding channels of the endoscope or in the exterior rotating part of the endoscope, while the interior part, to which the endoscope head is attached, does not rotate. The lengthening or shortening of the cannula as well as the change in its shape under the conditions of its elongation, are affected by co-ordinated linear movement in the desired direction and rotation of the endoscope or only of its rotating external part in the direction of the spiral winding during elongation, or in the direction of the spiral unwinding during the shortening of the cannula.

Description: A CANNULA OF CHANGEABLE LENGTHAND SHAPE Sphere of Technics The invention refers to a cannula of changeable length and shape, which can be used in medical application during the penetration of various devices, e.g. endoscopes, into the living systems as well as other activities, which necessitate the penetration into a medium, vulnerable to mechanical intervention and/or is without well-shaped confining walls. State of Art There are tubes, tubular elements (1-7) and devices., e.g. endoscopes, including tubes and tubular elements (8, 9), which are characterised by the fact that after penetrating into the body along the existing lumens - oesophagus, blood vessels, etc. - they ensure some protection from mechanical traumas to the surrounding tissues during the operation of the devices. A disadvantage of the existing tubes, tubular elements and devices containing tubes and tubular elements is the fact that during their penetration into the living system as well as during their removal, they cause considerable traumas due to the friction between their outside surface and the medium of penetration and particularly to the side pressure exerted by the sections where there are curves. The aim of the invention is to create a cannula of changeable length and shape, which is to penetrate the living system not only through existing orifices and which is to reduce to a minimum the traumas to the surrounding medium e.g. the human body. The task is solved by a device in which the cannula is formed at entering the working medium only through lengthening, which enters the working medium only through lengthening the front end, which takes the turns in any direction only through growing in the same direction and which is taken out of the surrounding medium only through shortening of the front end, keeping stable all the time in respect to the medium and keeping its shape. Technical Character of the Invention A cannula 1 has been created, built up of spirally wound one or more bands 2, which in the place of overlapping are linked by magnetic or other forces, while the free unlinked section of the bands 2 in the cannula wall are located freely in channels 5, parallel to the cannula axis and lying in the devices, e.g. the endoscope 3, for whose penetration in the surrounding medium the cannula is constructed. At the end of the endoscope 3, in the direction of its elongation, there is an enlargement, called head 4, which encircles the front end of the cannula 1, which is used to reduce to a minimum the traumatising of the surrounding medium during its elongation or shortening. Immediately under the head 4 are placed side openings through which the bands 2 pass from the channels 5 into the endoscope 3 to the cannula walls and vice versa. The change in the cannula length is affected by rotating the endoscope 3 or only its external concentric part, in which are located channels, simultaneously with co-ordinated penetration end removal of the endoscope 3, whereas the linear movement of the endoscope 3 per one revolution of the rotation is equal to the change in the cannula length 1 in the direction of the endoscope movement. The elongation of the cannula 1 is achieved by rotating the endoscope 3 or it external concentric part, in which the channels are located, in the direction of winding the spiral. During the movement of the bands 2 in the channels 5, in the direction of the endoscope end 3, is affected under the impact of being pushed receiving an impulse at the front end of the endoscope 3, outside the surrounding medium, or they are pulled by sections of bands 2 winding upon the cannula 1 , because of being fixed to the cannula walls by the forces of their interaction with the bend sections wound before that. The shortening of the cannula 1 is achieved by rotating the endoscope 3 or only its exterior concentric part in the opposite direction and pulling the bands 2 in the direction of the beginning of the endoscope 3 and the cannula 1 , whereby the bands 2 unwind front the spiral of the cannula 1 . The shape of the cannula 1 is changed by lengthening along the line of a turn in the desired direction, while the overlapping of the bands 2 forming the cannula 1 from the external side of the turn is smaller than their overlapping from the internal side of the turn. The advantages of the described cannula 1 are: The cannula 1 is static in respect to the surrounding medium with the exception of its end section, which can lengthen and shorten and thus the friction with this medium is eliminated, both of the cannula 1 itself and the endoscope inserted in it 3. The cannula 1 has a stable shape i.e. it is comparatively hard and that is why at the turns the cannula and the endoscope placed in it do not press laterally the surrounding medium. The described cannula 1 does not traumatise the surrounding medium either by longitudinal friction, or by lateral pressing except at the moment and in the place of its elongation and respectively shortening. Examples of Execution Example 1. A cannula 1 of changing length and shape, shown in fig. 1 and 2, built up of spirally wound band, the overlapping sections of which are linked by magnetic forces, while the unlinked section of the band in the cannula wall passes from the spiral into the interior of the cannula. In the interior of the cannula the free part of the band is located along the length of a guiding channel 5, included in the mass of the device, for whose penetration in the surrounding medium the cannula is designed, e.g. In the endoscope 3 ending with a head 4. The band 2 is a constant magnet with direction the axis of the poles, north-south, perpendicular to the axis of the band. The elongation of the cannula is selected by rotating the endoscope in the direction of the winding of the spiral, which is combined with pushing the band of the guiding channel 5 of the endoscope towards the cannula end and respectively the endoscope head, and at the same time for each revolution of rotation the endoscope moves in the direction of the cannula elongation with a length equal to the elongation of the cannula for the same revolution. The shortening of the cannula is effected by rotating the endoscope in the direction of unwinding the spiral, combined with pulling the band in the guiding channel towards the beginning of the cannula and the endoscope and taking out the endoscope with a length equal to the shortening of the cannula for the same revolution. The shape of the cannula is changed during its elongation by forming turns as the endoscope head bends in the direction of the turn whereas the overlapping of the separate section of the band in the coils of the spiral is smaller from the external side of the turn than from its internal size. Example 2. A cannula 1, shown in figures 3 and 4, similar to Example 1, which is built up by the combined winding of two concentrically situated spirals of two bands 2 and 2', in which one band 2' forms the internal spiral, overlaps simultaneously with its width half of the widths of two coil of the band 2, forming the external spiral. Separately in each of the two concentric spirals, located over each other, coils as a rule do not overlap. But such overlapping can be obtained from the internal side of a turn in the cannula. Example 3. A cannula 1, shown in fig. 5, similar to the cannula in Example 1, in which the endoscope 3 is divided into two concentrically located parts - interior 3 and exterior 3', the guiding channels is located in the mass and along the length of the external part of the endoscope 3'. This allows, during the change of the length and the shape of the cannula, the rotation only of the external part 3' of the endoscope, in which is located the guiding channel 5, while the interior part and the head connected with it does not rotate. The endoscope head 4 is connected only with its interior part 3. The rotating part of the endoscope 3' can be used for placing e.g. fibrous optics, conducting the light to the object observed by the endoscope, whereat the front part of the head is transparent. The advantage of this cannula is that the rotating movement of the head is avoided and thus the traumatising of the surrounding medium during the penetration of the head into it is reduced to a minimum. Literature ^ 1. Author's certificate CCCP SU 1477371A1 (11.05.86) 2. Author's certificate CCCP SU 1480806A1 (06.07.87) 3. Author's certificate CCCP SU 1819566A1 (17.04.91) 4. Author's certificate CCCP SU 1099949A1 (25.02.82) 5. Author's certificate CCCP SU 1819567A1 (28.06.91) 6. Patent USA 5643174 (01.07.97) 7. Patent USA 5620408 (15.04.97) 8. Author's certificate CCCP 925310 (15.01.79) 9. Patent PF RU 2022518 CI (13.02.91) 10. Patent USA 5558665 (24.09.96) 11. Patent USA 5448989 (12.04.95) 12. Patent USA 5645520 (08.07.97) 13. Swedish patent 9604792-3 Description of attached figures Fig. 1 - LONGΓTUDINAL VIEW AND PARTIAL SECTION 1. Cannula 2. Bands, building up the cannula 3. Endoscope 4. Endoscope head 5. Guiding channel of the band Fig.. 2 - CROSS SECTION ALONG AB 1. Cannula 2. Band 3. Endoscope 5. Guiding channel of the band Fig. 3 - LONGITUDINAL VIEW AND PARTIAL SECTION 1. Cannula 2 and 2' - Bands 3. Endoscope 4. Endoscope head 5 and 5' - Guiding channel of the bands Fig. 4 - CROSS SECTION ALONG AB 1. Cannula 2 and 2' - Bands 3. Endoscope 5 and 5' - Guiding channel of the band

Claims: Patent claims 1. A cannula 1 of changing length and shape, built up of spirally wound one or more bands 2, characterised by the fact that the free unlinked sections of the bands in the cannula wall, are inserted in the interior of the cannula and during the elongation of the cannula they slide in the direction of the growing end of the cannula, while during the shortening of the cannula they slide in the direction of the beginning of the cannula. 2 A cannula 1, according to Claim 1 , characterised by the fact that the bands 2, wound spirally in the shape of a tube, have the properties of a constant magnet and the fixing of the separate coils in the spiral is increased by their magnetic interaction. During the shortening of the cannula the endoscope moves fluently in the direction of its exit from the surrounding medium and at the same time it rotates in the direction of the unwinding of the spiral, whereat the liberated parts of the bands get inserted laterally into the guiding channels 5 and slide along them in the direction of the beginning of the cannula and the endoscope, while the change in the shape of the cannula is achieved when during the elongation the endoscope head bends in the desired direction, whereat the band from the external side of the turn overlap with a smaller width of the bands from the consecutive coils of the spiral than from, the internal side of the turn. 3. A cannula, according to Claim 1, characterised by the fact that when the bands building up the cannula are more than one, each of them forms a separate channel concentrically located in respect to the rest, and the bands from one concentric channel overlap with their width part of two consecutive coils of the neighbouring concentric channel. 4. A cannula, according to Claim 1, characterised by the fact that the free unlinked parts of the bands in the cannula wall are located in guiding channels 3 of the device e.g. the endoscope 3, for whose penetration in the surrounding medium the cannula is designed. 5. A cannula, according to Claim 4, characterised by the fact that during the elongation of the cannula, the endoscope 3 moves in the direction of its penetration into the surrounding medium and at the same time it rotates in the direction of the spiratwmding, while the bands slide in the guiding channels 5 in the direction of the growing end of the cannula, and at this end they turn aside towards the cannula wall, wind up upon it, forming the consecutive coils and linking with them by magnetic forces into a stable cannula wall, while during the shortening of the cannula the endoscope moves smoothly in the direction of its exit from the surrounding medium and at the same time it rotates in the direction of the spiral unwinding, whereat the liberated parts of the bands get inserted laterally Into the guiding channels 5 and slide in them in the direction of the beginning of the cannula and the endoscope, and the change in the cannula shape is achieved during the elongation when the endoscope head bends in the desired direction, while the bands from the external side of the turn overlap with a smaller width the bands of the consecutive coils of the spiral than from the internal side of the turn. 6. A cannula, according to Claim 5, characterised by the fact that the sliding of the bands in the guiding channels is assisted by pushing when the cannula is elongated, and by pulling when the cannula is shortened. 7. A cannula, according to Claim 5, characterised by the fact that the guiding channels are located in the exterior part 3' of the endoscope, representing a tube, concentrically including the remaining part of the endoscope 3, which during the lengthening or shortening of the endoscope rotates in the direction of winding and respectively unwinding the spiral only the exterior part of the endoscope, and the interior part does not participate in the rotating movement, whereas both parts of the endoscope penetrate into and get out of the surrounding medium with a speed which coincides with the speed of lengthening or shortening the cannula.

Inventors: STEFANOV ALEXANDER R, STEFANOV IVAN R, STEFANOV, ALEXANDER R., STEFANOV, IVAN R.
Applicants: STEFANOV ALEXANDER R, STEFANOV IVAN R, STEFANOV, ALEXANDER R., STEFANOV, IVAN R.
Application year: 1999
Main classification: A61B1
IPC codes: A61B1, A61B17, A61M25