ULTRASONIC ENDOSCOPE PROVIDED WITH PROTECTIVE SHEATH

Abstract: A method and device are described for fitting a flexible elongated thin-walled protective sheath (1, 2, 3) around the head and transmission tube of an ultrasonic endoscope. First the protective sheath is slid onto the nozzle section (4) of a fitting funnel in a gathered condition. The head and transmission tube are then fitted into the protective sheath via the mouth (5) of the fitting funnel. By moving the fitting funnel along the transmission tube the protective sheath is pulled taut to the head and transmission tube.

Description: T i tle: ULTRASONIC ENDOSCOPE PROVIDED WITH PROTECTIVE SHEATH The invention relates to a method and device for fit¬ ting a flexible elongated thin-walled protective tube around a head used for diagnostic purposes and an elongat¬ ed transmission tube joined thereto for transmitting image signals originating from the head. Such a method and device, as well as a protective tube to be used therewith, are known from the US Patent 4,646,722 According to a method known therefrom, the open end of a protective tube to be fitted is attached in an air¬ tight sealing manner to an annular seating of an inflating sleeve. Said sleeve is provided with a connecting nipple via which blower air can be fed to the interior of the sleeve and the protective tube attached thereto. Said sleeve is also provided with an annular sealing element fitted therein which is intended to enclose in an air- tight sealing manner the transmission tube which is join¬ ed to the diagnostic head. After said sleeve has been itted at the end where said diagnostic head is located, ie. around the transmis¬ sion tube, air is fed via the connecting nipple, as a result of which the protective tube attached to the sleeve is inflated. As a result of this it is possible to pull the sleeve and the protective tube over the transmission tube, the sealing element of the sleeve being slid over the outer surface of the transmission tube. Once said transmission tube is surrounded by the expanded protective tube over the desired lengtn, it is arranged that the air is able to escape, as a result of which t e protective tube encloses, in a close fitting manner, the transmission. tube and the diagnostic head joined thereto. This known technique is laborious and t me-consuming. In addition, it is a requirement that a source of com¬ pressed air is available. Viewed from a factory engineei— ing viewpoint it is also unattractive for the sleeve to have to continue s multaneously to form an airtight seal in this process while being slid over the transmission tube. The object of the invention is to meet the drawbacks outlined above. For this purpose a method according to the invention is cha acterized by the following steps: a) with the exception of a relatively short and sealed en section, the protective tube is slid onto the nozzle sectio of a fitting funnel in a manner such that the protective tube is situated on said nozzle section in a shirred condi t ion; b) the head and the section of the transmission tube join thereto is fitted therein via the enlarged section of the fitting funnel and displaced with respect thereto in a manner such that said head is situated in the protective tube and has reached the said end section of the protective tube; and c) the transmission tube is held in position while the f i ting funnel and the section of the protective tube present thereon are moved over the transmission tube until said pro tective tube has assumed the stretched condition. A method proposed by the invention makes it possible to effect a pertinent assembly of diagnostic head and transmission tube in a protective tube in an efficient and simple manner. The method according to the invention can be used th advantage in those cases in which the head used for diagnostic purposes s an ultrasound transducer. In this case it is necessary for such a transducer to be acouεtic- ly coupled to a transmission medium whi h conducts ultra¬ sound well. For this purpose use is generally made cf a transmission gel. Since such a gel has a certain lubri¬ cating action, it is necessary, in view of a required fac¬ ility to rotate the transducer around the longitudinal axis of the transmission tube, that only the transducer is in co tact with gel so that no transmission gel is present betwee tne inside wall of the protective tube and the outer surfac of the transmission tube. A method suitable for the above-mentioned use is, ac¬ cording to the invention, characterized in that, after the step in which, with the exception of a relatively short and sealed end section, the protective tube is slid onto the no zle section of a fitting funnel in a manner such that said protective tube is situated on said nozzle section in a shi red condition, and prior to the step in which the transduce and the section of the transmission tube connected thereto are fitted ' therein via the enlarged section of the fitting funnel and are displaced with respect thereto in a manner such that said head is situated in the protective tube and has reached the said end section, a certain quantity of transmission medium which conducts ultrasound well is in¬ jected into the said end section of the protective tube via the enlarged section of the fitting funneL; and the trans¬ ducer is displaced in the protective tube in a manner such that said transducer is acoustically coupled to the inject- ed transmission medium. As is reported in the above-mentioned US patent 4,646,722, an assembly of diagnostic head and transmission tube is often used in combination with an operating case from which, inter alia, the doctor in attendance can manipulate the transducer. It is usual to cause such an operating case to be connected to said transmission tube on the side facing the transmission tube via a conically sloping section. Within the framework of the invention a detachable snap coupling may be achieved between the fittin funnel and the operating case in a simple manner. In vie of this, the method according to the invention characterized in that the end section of the rotective tube situated on the fitting funnel is splayed out around the rim of the enlarged funnel section. After use, the fitting funnel with the section of th protective tube splayed out around it can be decoupled fr the operat ng case in a s mple manner, it be ng possible remove said funnel and the protective tube from the trans mission tube and transducer. After this the protective tube is detached from the funnel nozzle and thrown away. A device used for applying a method according to the invention is character zed, according to the invention, b fitting funnel which is capable of aLlowing through a per nent diagnostic head; and is further characterized in tha the outside dimensioning of the nozzle section of the fit ting funnel and the inside dimensioning of the protective tube are matched to each other in a manner such that the tective tube, regarded up to_ the end of the said end sect can be slid over the nozzle section; and the length of th nozzle section is short in comparison with the Length of pertinent transmission tube. A protective tube to be used in a method according r the invention is, according to the invention, character z by a segment, ad oining the open end section of the prote ive tube whose passage cross sections, regarded over the Length of said segment, are smaller than the passage cros sect ons regarded over the length of the said open end se ion; and each passage cross section of the said segment is larger than the maximum contour cross section of "the nozzle section of the fitting funnel. Such a protective tube, when it has to be used in cor bination with an ultrasound transducer, is characterized, according to the invention, in that the said relatively short and sealed end section of the protective tube has internal cross sections, viewed over virtually the whole length cf said end sectio , which are -each smaller than the passage cross sections of said segment. The invention will be exDlainec in more cetail Delov ith reference tc the drawing, herei : Figure 1 gives a view of an illustrative exemplary embodiment of a protective tube to be used within the framework of the invention; Figure 2 shows an embodiment, portrayed partially in section and partially in view, of a fitting funnel used for applying the method according to the invention; Figure 3 portrays d i agrammat i ca 11 y the situation in which, during the implementation of the method according to the invention, a protective tube of the type portrayed in Figure 1 is fitted in the shirred condition on the nozzle section of the fitting funnel of the type portrayed in Figure 2; and Figure 4 portrays d i agrammat i c a 11 y the situation in which, as a further phase of the method according to the invention, a section of the protective tube is pulled off the nozzle section of the fitting funnel and is brought to the stretched condition. Without being limited thereto, the invention will be explained in more detail below by a description of an exemplary embodiment in which an ultrasound transducer and a transmission tube joined thereto have to be fitted in the interior of a protective tube. In this connection, various types of transducer are usual such as, for example, a transducer having, for example, 64 elements, which depending on the control electronics, can cause an image to be displayed of an object to be investigated within a se tor-shaped frame or within a rectangular frame. According to a conc-eived application, such a trans- ducer is used to form, from the oesophagus, images of the heart, which is located in the vicinity thereof, or other organ-ε, or to form images of other organs from other open¬ ings in the body. Before it is possible to introduce the assembl cf transducer and transmission tube into the oesop agus, it is necessary tc fi sai assembly in the interior of a protective tube. T is is a flexible thin- alle tube which is open at the one end and closed at the other end and which, for example, is manufactured from latex rubber. In Figure 1, shape and dimensions are shown which are il¬ lustrative of such a protective tube. The exemplary embodiment of a protective tube por¬ trayed in Figure 1 comprises a reservoir segment 1, an intermediate segment 2 and a feed segment 3. It is the intention that the transducer is finally situated in the reservoir segment and is surrounded there by an acoustic transmission gel, while the transmission tube via which the image signals formed by the transducer are removed extends through the interior of the intermediate segment 2 and the feed segment 3 to an operating case (not shown). Attention is drawn to the fact that use is usually made of a transducer whose working region is directed trans¬ versely with relation to the —longitudiπal axis of the transmission tube. At the same time, it should be pos¬ sible for the transducer to be rotated around said longitudinal axis in order to be able to observe a pertin- ent organ, such as, for example, the heart, from various angles- In view of this, it is necessary for no trans¬ mission gel to be present between -the inside wall of the intermediate segment 2 and the outer surface of the trans¬ mission tube extending through the interior of said seo- ment. After all, only then is it possible to rotate the transmission tube and, consequently, the transducer about the longitudinal axis by means of a section of the inter¬ mediate segment situated outside the patient. In order to carry out the method according to the in- ventioπ use shoulα be made of a fitting funnel. An exemplary embodiment illustrative of this is shown in Figure 2. Such a funnel comprises a nozzle sec¬ tion 4 and an enlarged debouchment section 5. The central funnel opening 6 is dimensioned in a manner such that the pertinent transducer and the transmission tube joine tc it can be guided through sa d funnel. For the met od of the invention it is furthermore necessary that the relatively long protective tube, with the exception of the reservoir segment 1 and the junction segment adjacent thereto can be slid by hand onto the outer surface of the nozzle section 4. For this purpose, the dimensioning of said nozzle section and the protect¬ ive tube are matched to each other. This means that the minimum inside diameter of the intermediate segment 2, which is© = 18 mm in the exemplary embodiment portrayed, is to some extent larger than the outside diameter of the nozzle section 4 of the fitting funnel. The result of the manual operation referred to above is portrayed dia¬ grammatica I ly in Figure 3. The feed segment 3 is, under these circumstances, splayed out around the rim of the debouchment section 5 of the fitting funnel, the other section of the protective tube being situated in a more or less shirred condition arαund the nozzle section 4. When the assembly of protective tube and fitting funnel is brought to the condition outlined above, the freely protecting reservoir segment ! can be filled with trans- mission gel. For this purpose, use may be made of a con¬ ventional hypodermic syringe and a narrow dosaging hose line connected thereto. A predeter ined quantity, for example, 1 cm , of transmission gel is thus injected via th-e fitting funnel into the reservoir 1 of the protective tube. As the next step, the transduc-er and a section of i-.'ie transmission tube adjacent thereto are guided through the central channel 6 of the fitting funnel until said transducer is situated in the interior of the reservoir segment 1 and is acoustically coupl-ed with the trans¬ mission gel introduced into the latter. The transmission tube is then held in pLace while the fitting funnel is moved over it in a direction moving away from the trans¬ ducer, which, like the transmission tube remains in its place. During said movement, the section cf the protec¬ tive tube situated on t e nozzle section is successively pulled off of said nozzle section. An instantaneous record of this unrolling operation is portrayed diagram- atically in Figure 4. The result can thus be achieved that the transducer and the transmission tube joined thereto are enclosed by the protective tube while only the transducer is in con¬ tact with transmission gel. Via the debouchment section 5 of the fitting funnel, the assembly consisting of protective tube and fitting funnel can then be rigidly coupled to the operating case. For this purpose, the fact is beneficial that an end sec¬ tion of the protective tube is splayed out around the de¬ bouchment rim of the fitting funnel. With the succession of steps described above, a situation has arisen in which the transducer and transmission tube, enclosed by the protective tube can be introduced into the body of a patient to be examined. After the examination has been completed and the transducer and transmission tube enclosed by the pro¬ tective tube have been removed from the patient, the fit- ting funnel is decoupled from the operating case. After this, said fitting funnel and the protective tube attach¬ ed thereto can be removed from the transmission tube and the transducer. Finally, the protective tube is removed from the nozzle section and the debouchment section in order to be thrown away. In principle, the cross sections of the protective tu and the fitting funnel may have a shape different from the circular shape such as, for example, an oval shape. In view of the manufacturing technology, the inter ed ate segment of the protective tube is preferably shaped so as to extend somewhat conically as is evident from Figure For the sake of completeness, attention is drawn to the fa that the diameter dimensions portrayed in Figure 1 indicat a pertinent inside diameter of the protecti e tube. The wall thickness of the protective tube is aporox0~25 mm. I an ultrasound transducer is used, the protective tupe shou obviously be transparent to ultrasound. It is also possible to make use of a transducer, the working field of which extends from the head section of th reservoi r . The invention is also applicable to the field of endo copy, as described in the US Patent 4,646,722.

Claims: CLA I MS 1. Method for fitting a flexible elongated thin-walled protective tube around a head- used for diagnostic purposes and an elongated transmission tube joined thereto fortrans- mi"ttirvc; image signals originating from the head, charactei— ized by the following steps: a) with the exception of a relatively short and sealed end section, the protective tube is slid onto the nozzle section of a fitting funnel in a manner such that the pro¬ tective tube is situated on said nozzle section in a shii— red condition; b) the head and the section of the transmission tube joined thereto is fitted therein via the enlarged section of the fitting funnel and displaced with respect thereto in a manner such that said head is situated in the protective tube and has reached the said end section of the protective tube; and c) the transmission tube is held in position while the fitting funnel and the section of the protective tube present thereon are moved over the transmission tube until said protective tube has assumed the stretched condition. 2. Method according to Claim 1 and intended for the case in w i h the head used for diagnostic purposes is an ultrasound transducer, characterized in that, after the step a) and prior to the step b), a certain quantity of transmission medium which conducts ultrasound well is in¬ jected into the said end section of the protective tube via the enlarged section of the fitting funnel; and in the case of the step b), the transducer is displaced in the protect¬ ive tube in a manner such that said transducer is acoustic- ally "coupled to the injected transmission medium. 3. Method according to Clai 1 or 2, characterized in that the end section of the protective tube situated on - the fitting funnel is splayed out around the rim of the enlarged funnel section. 4. Device for applying the metho according to one of the preceding clai s, characterized by a fitting funnel which is capable of allowing through a pertinent diag¬ nostic head; and is further characterized in that the out¬ side dimensioning of the nozzle section of the fitting funnel and the inside dimensioning of the protective tube are matched to each other in a manner such that the pro¬ tective tube, regarded up to the said end section, can be slid over the nozzle section; and the length of the nozzle section is short in comparison with the length of the per¬ tinent transmission tube. 5. Protective tube to be used in the method according to one of Claims 1-3, characterized by a segment, ad¬ joining the open end section of the protective tube whose passage cross sections, regarded over the length of said segment, are smaller than the passage cross sections re- garded over the length of the said open end section; and each passage cross section o-f -the said segment is large than the maximum contour cross section of the nozzle sec¬ tion of the fitting funnel. 6. Protective tube according to Claim 5 and to be used in the method according to Claims 2 or 3, characterized in that the said relatively short and sealed end section of the protective tube has internal cross sections, view¬ ed over virtually the whole length of said end section, which are each smaller than the passage cross sections of said segment.

Inventors: STOLK ALBERT FRITS, STOLK, ALBERT, FRITS
Applicants: OPTISCHE IND DE OUDE DELFT NV, B.V. OPTISCHE INDUSTRIE "DE OUDE DELFT"
Application year: 1988
Main classification: A61B8
IPC codes: A61B1, A61B8, A61B19