Transporter for controlling the longitudinal movement of an electrode

A transporter for controlling the longitudinal movement of an electrode of a urological resectoscope, with a guide tube which is secured lengthwise on the resectoscope and on which a carriage is mounted so as to be longitudinally movable, with a spring mounted at one end on the carriage and at the other end on one of the ends of the guide tube, and with finger supports secured on the carriage and on one of the ends of the guide tube, is characterized in that the spring is formed in one piece with at least one of the finger supports, and wherein the spring is designed as a leaf spring and has portions curved in opposite directions.

The invention relates to a transporter of the type mentioned in the preamble of claim1.

Resectoscopes of the generic type are used mainly in urology, where they are used primarily for the purpose of reducing the size of a hypertrophic prostate by resection of the urethra, that is, from the inside. However, resectoscopes can also be used in other surgical fields, such as for procedures in the uterus, for example.

Resectoscopes having transporters of the generic type constitute the standard construction in the prior art. They comprise a shaft tube in which an electrode carrier is arranged so as to be longitudinally movable, which can cut with an electrode in the area of the distal end of the shaft tube. In the process, the cut is usually made against the distal margin of the shaft tube. Commonly, the cut is made using a high-frequency current. Therefore, the distal end area of the shaft tube is normally configured to be insulating.

The electrode carrier is connected at its proximal end to the transporter by means of which it can be moved in the longitudinal direction in order to perform the cutting movement. The transporter is usually detachably fastened to the proximal end of the shaft tube, and comprises a carriage mounted so as to be longitudinally movable, by means of which the electrode carrier can be coupled for the shared longitudinal movement.

The actuation of the transporter usually occurs using the fingers of one hand, which on the one hand touch the carriage, and on the other hand touch the stationary portions of the transporter, which are firmly connected to the guide tube The movement of the transporter according to the prior art occurs against a resetting spring, which is usually configured as a leaf spring in the generic transporter. The spring is fastened with one end to the carriage and with the other end to the guide tube. Several possibilities exist, depending on whether an active or a passive transporter is needed, and whether the spring is to operate as a compression spring or as a tension spring.

The cut is usually made with a retraction movement of the electrode. In the case of the active transporter, the electrode is pulled back against the spring force (in the proximal direction). In the case of the passive transporter, the electrode is moved forward by hand and then released so that it is pulled back in a cutting movement by the spring force. The resetting spring is designed as a leaf spring according to the generic prior art.

In these constructions, the spring is not only used for generating the resetting force applied to the electrode, but also uses the torsion-limiting property of the leaf spring to prevent twisting of this carriage, which, according to the prior art is usually mounted on a round guide tube which is present in the resectoscope for guiding the optic system.

Looking more closely at the generic constructions, one notices the use of a simple leaf spring which, however, has a surprisingly complicated construction. In each case the leaf spring is gripped at the ends, usually in a plastic block. This plastic block is hinged via an axial hinge to the carriage and to a stationary portion of the transporter, respectively. All this requires the use of various materials and complicated construction and manufacturing steps.

At the ends of the leaf spring there is [sic], as the known constructions show, in each case in the area in which finger rests are provided on the transporter. These are components which the operator touches with the fingers in order to operate the transporter. The proximal rest is usually configured as a finger ring. A finger rest for placing one or several fingers is provided distally. One commonly also finds two finger rests here that are provided above and beneath the guide tube. The finger rests have no other design functions, and are generally configured as plastic shells that are fastened to the carriage and components, respectively, which are situated at one end of the guide tube. The finger rests are thus situated where the spring also engages, as a result of which the construction becomes more complicated.

U.S. Pat. No. 5,843,017 A discloses a medical instrument with a transporter, in which a carriage is longitudinally movable by compression of a U-shaped handle. It is proposed to arrange a leaf spring for spring preloading of the carriage in the housing of the instrument, coaxially around a guide tube and distally with respect to the handle.

The object of the invention is to provide a generic transporter that has a simpler and more cost effective construction.

This object is achieved with the features of the characterizing portion of claim1.

According to the invention, the spring is configured to form a single piece with at least one of the finger rests, preferably with all the finger rests according to claim2. According to claim3, the integrated component thus produced is made entirely of spring-resilient plastic that has sufficient properties for the spring purposes.

The result is a single-piece construction which, in the affected construction area, replaces, as a single piece, the essential elements engaging there, that is, in particular the spring and the finger rests. This causes no problems in tennis of material technology. The construction can be made from metal or preferably from plastic. Plastics with appropriate spring properties are commercially available and also have the strength values required for the finger rests.

The manufacturing of the transporter is considerably simplified by the construction element provided by the invention. The construction element, of which there is now only one in this area, is connected at the two ends to the transporter by a screw connection or other connection possibilities. All other mounting steps required heretofore, such as in particular the premounting of the spring comprising multiple parts, the separate mounting of the spring and the finger rests, and the like are dispensed with. The result is a considerable saving effect. In addition, the invention provides a single-piece component, which in comparison to multipart components has the advantage of being gap-free and thus easier to clean.

Additional saving possibilities exist due to the single-piece manufacture of a relatively complex component. The entire component can be injected-molded from plastic, for example, so that significant saving effects result, even in medium-size series.

The construction according to the invention also allows deviations from the U-shaped configuration of the leaf spring, which was always preferred in the past for manufacturing reasons. In the case of manufacture by injection molding, or, for example, by cutting out or stamping from a plate, springs having shapes of any degree of complexity can be used at low cost. Thus, in particular, the embodiment according to claim4can be used, wherein the spring comprises sections bent in opposite directions. As a result, the course of the spring force over the path can be optimized. For example, the spring can be configured in the shape of an S in some sections, wherein two sections of the S-shaped spring area in each case are bent in opposite directions. A first bulge of the S shape is bent in a first direction, and a second bulge of the S shape is bent in a second, opposite direction. A spring area can also have a C-shaped configuration, for example wherein the end sections of the C-shaped spring area are bent in opposite directions.

FIG. 1shows, in a side view, a urological resectoscope1with a shaft tube2which in the usual configuration is made of metal, but which in its distal end area3is made of an insulator, for example ceramic. At the proximal end of the shaft tube2, there is an end body4which is configured as a detachable coupling piece, using means that are not shown.

A transporter5, which is illustrated in an enlargement inFIG. 2, can be coupled to the end body4.

FIG. 2shows a coupling part6of the transporter5, which for the coupling fastening is insertable into the end body4.

An electrode carrier7extends through the shaft tube2, and extends through the coupling piece6so as to be longitudinally movable and fastenable in a carriage8of the transporter5by means of a locking button9. The electrode carrier7can be moved in the longitudinal direction of the shaft tube2by longitudinal movement of the carriage8. In this way, an electrode10arranged at the distal end of the electrode carrier7can be adjusted longitudinally, the electrode usually being configured in the shape of a U.

The carriage8is mounted, so as to be longitudinally movable in the direction of the shaft tube2, on a guide tube11which passes through the coupling piece6and is fastened thereto.

The guide tube11is fastened to an end plate12at the proximal end. The carriage8can be moved on the guide tube11from the distal stop on the coupling piece6to the proximal stop on the end plate12.

As a result, the electrode10can be longitudinally adjusted in the area of the distal end of the shaft tube2. The construction is usually configured in such a manner that the electrode10cuts against the lower area of the distal margin of the end area3. All this occurs within the viewing area of an optic system13, shown only in broken lines inFIG. 1, which can be inserted from the proximal end of the transporter5through the guide tube11into the work position illustrated.

By means of the illustrated resectoscope1, it is possible in particular to cut off tissue in the prostate in fairly large, flat pieces. Bleeding that occurs in the process, causing impediments to vision, is controlled in the usual way by rinsing with a clear rinsing fluid. To accomplish this, the illustrated resectoscope1uses the usual continuous permanent rinsing. Rinsing fluid is led into and out of the shaft tube2at connections14and15. In the interior, the shaft tube2is subdivided into two channels, for example, by means of a dual tube system. One of the channels runs rinsing fluid through the distal opening of the shaft tube2, while the other channel allows rinsing fluid to flow out of lateral openings16of the shaft tube2.

Working with such a resectoscope1requires the utmost manual skill and continuous mental alertness in overviewing the complicated surgical area located inside the prostate, which is closed off from the outside and which the surgeon must envision in three dimensions in order to be able to work in it, pushing and rotating in all directions in a controlled manner.

For this purpose, particularly exact and finely sensitive operability of the transporter5is required. From the transporter, it must be possible to control the electrode10with utmost precision in all directions in all the movement sequences.

In the usual technique with a resectoscope1of the illustrated design, a drawing cut is made. For cutting, the electrode10is pulled back in the proximal direction. Shortly beforehand, the cutting voltage is applied to the electrode10, which for this purpose is connected via the electrode carrier7and the carriage8and beyond same to a high-frequency generator with a switch configured as a foot switch, for example.

To make a cut at a certain site and in a certain rotation position, the resectoscope1is moved to the site of the cut with the electrode10distally extended. The voltage is then switched on and the carriage8is subsequently pulled back in the proximal direction. The voltage is then switched off and the electrode is moved back into the initial position.

In the construction represented inFIG. 1, the retracting movement of the electrode10used for cutting is generated by hand by touching with the fingers of one hand the carriage8on the one hand, and the end plate12on the other hand. Finger rests are situated at the corresponding sites in order to improve the sensitive operability.

As shown inFIG. 2, the finger rests are a finger ring17which is attached to the end plate12and into which the operator sticks his/her thumb18. An upper finger rest19and a lower finger rest20are fastened to the carriage8. In the process, the upper finger rest19is used for resting the index finger21, and the lower finger rest20is used for resting the middle finger22and the ring finger23. As can be seen inFIG. 2, the upper and the lower finger rests can each be configured as a web. As provided in this exemplary embodiment, the finger rests19,20in each case can comprise a distal front side with a contact area for resting the fingers, and a rear side facing the contact area and not in contact with the fingers.

In the construction according to the invention illustrated inFIG. 1and in particular inFIG. 2, the retracting movement of the carriage8used for the cutting occurs against a spring24which braces the carriage with respect to the end plate12. This ensures that after the retracting cutting movement, the carriage8with the electrode7is again moved automatically in the distal direction back into the starting position.

A so-called active transporter is involved here. However, in some countries the passive transporter is preferred. In the case of the passive transporter, the spring could be arranged exactly as inFIG. 2. However, it would be used as a tension spring. The finger ring17would then be situated on the carriage8, and the finger rests19and20would be situated on the coupling piece6. Due to the finger action, the carriage8would thus be moved in the distal direction and then automatically returned under the action of the spring, in the process of which the cut is made.

FIG. 2shows an active transporter with a spring24to which pressure is applied. A tension spring could also be used, which would then have to be arranged between the carriage8and the coupling piece6.

As is also known from the prior art, the spring24is configured as a leaf spring, shown in cross section inFIG. 3. In the prior art, such a leaf spring would be coupled to end pieces, which could also be made of other materials, wherein the leaf spring is usually made of metal. The finger rests17,19and20would have to be mounted separately.

In the present invention, the spring24is formed as a single piece with the distal finger rests19and20, wherein the distal finger rests19and20have a continuous design with a middle part25, which is fastened to the carriage8via a fastening means26, for example, a screw. As can be seen inFIG. 2, it is provided that the spring24is connected to the finger rest in the back area thereof. This prevents inadvertent touching of the spring24or a portion of the spring24when the carriage8is moved due to finger pressure. As a result, complex spring shapes can be used, wherein the spring mechanism or the spring action achieved by the spring mechanism is protected against undesired influence due to contact with the fingers. It is particularly advantageously conceivable to arrange the spring24vertically—viewed in the transverse direction with respect to the guide tube11—between the guide tube11and the contact areas provided for the fingers, so that the spring24engages vertically between the fingers and the guide tube11. This ensures a good spring action of the transporter and promotes particularly smooth movement of the carriage8.

At the other end of the spring24, the spring is also designed in a single piece with an end piece27that is fastened to the end plate12via a fastening means28. The spring24together with the proximal end piece27and the parts19,20and25fastened to the carriage8are designed as a single piece. This complex component can be injection-molded from plastic, for example, or stamped or cut out from a plate of appropriate thickness, for example by means of a laser. The material must have appropriate spring properties and sufficient strength.

The spring24can have a U shape, for example, as in the prior art; however, according toFIG. 2, it is advantageously configured with the curved sections24′ and24″ which in each case comprise sections bent in opposite directions. For example, it is possible to provide that the end areas of a curved section24′,24″ are not oriented parallel, as in a U shape, but instead point in opposite directions. For example, as indicated particularly inFIG. 2, the curved sections24′ and24″ can be curved in the shape of a C. The end areas of the C shape point in opposite directions.

An S-shaped course of a curved section24′,24″ (not shown) is also conceivable, wherein, for example, the end areas of a curved section24′,24″ extending in the shape of an S point in opposite directions. Alternatively or in addition to the end sections of the curved sections24′,24″, other sections can also have opposite bends. For example, in an S shape—relative to a direction—a convex and a concave curvature are provided which form two sections that are bent in opposite directions.

As indicated inFIG. 2, the curved sections24′,24″ can form spring legs of the spring24. It is also conceivable for at least one spring leg of the spring24to comprise multiple curved sections24′,24″. In addition, it is conceivable for some of the curved sections24′,24″ to be arranged parallel to one another or at a substantially constant distance from one another.

In the exemplary embodiment according toFIG. 2, it has been considered that the bent sections24′ and24″ are configured in each case with one of their end areas converging to a tip relative to one another. The two curved sections24′ and24″ thus transition into one another at a tip29in this exemplary embodiment. The result is a geometrically highly complex shape that has advantageous bending properties, in particular to ensure a suitable force progression over the movement range of the carriage8.

In the embodiment represented inFIG. 2, the finger ring17is not formed as a single piece with the spring24, and can be made of metal, for example, while the spring24is made of plastic.

In the proximal end area, the spring24is formed as a single piece with the end piece27. In an alternative design, this end piece can be formed as a single piece with the end plate12, which then can also be formed as a single piece with the finger ring17. The principle of the invention can be advantageously expanded in this way.