Laparoscopic instrument

The invention relates to a laparoscopic instrument having a handle, one from the handle supported shaft and, arranged at the distal end of the shaft working head, the shaft having a distal, bendable section and for adjusting the Curvature of the bendable portion of a wire or rope formed tensile element extends from the region of the handle beyond the curvable portion and distal to the Side of the bendable portion on the shaft or on the working head is fixed and in the field the handle disposed actuator to the tension element to tensile loading cooperates with the tension element and through the bendable section more in longitudinal direction of the bendable portion spaced guide bracket arranged for the pulling element.

Laparoscopic instruments are surgical instruments laparoscopic operations. In such an access opening into a body cavity at the desired for engagement created body. In order to create such an access opening normally be trocars used. Such trocars are sleeve-shaped and have a through channel, through which the operation by means of laparoscopic instruments executed becomes. This surgical technique is one of the minimally invasive surgical techniques (LIS) technique.

Known laparoscopic instrument includes a handle, a raised from the handle And a shaft arranged at the distal end of the shaft working head in which a distal portion of the shaft krümmbarer of several pivotally interconnected Members is formed. In addition to a tensile member disposed from the handle Actuator can be acted upon, runs a second cable through the bendable section, the e is inerseits, on the other hand fixed to the handle on the working head and to what a coil spring is arranged. This second cable is used, the bendable section straighten when interacting with the operating part tension element not be attracted and moved about this operating part, but left loose becomes. The adjustable curvature of the bendable section is intended to work with the head to bypass structures inside the body, for example, hollow organs or vessels. With the working head, for example, as a consequence, an implant, a thread or other Subject to the hollow organ or vessel to be pulled around. A disadvantage of this conventional Instrument is among others its relatively complicated structure to appropriate Returns this instrument leads. Furthermore, a residue-free cleaning is this Instruments after performing an operation practically impossible. Between the links the bendable portion and the pull ropes contact during surgery and blood Body fluids determined, of which even after rinsing and sterilization of instruments Residue remains, which lead to a risk of infection.

It is known further, for example, from DE 41 33 800 C1, a laparoscopic instrument, wherein the distal end of an attached to a handle tube is a leaf spring is pushed out, by means of a handle arranged on the actuation organ. The leaf spring is clamped in the tube lying within state and accepts the Pushed out of the tube its predetermined curvature at which it no external force acting having forces. The distal end of the leaf spring in this case forms the working head of the Instruments. This working head is used for example for the dissection of tissue and can also be provided with a slot into which an object, for example, thread, suspended is around it in order to pull a hollow organ or vessel. A disadvantage of this Instrument including the problematic cleaning, especially of front in the end the tube penetrated body fluids. Also there are limitations regarding changes in the radius of curvature adjacent to the working head section.

A bypass instrument with around an object definable, elongated, stretchable and deflectable arm, at whose free end a holding tool being arranged, said arm at least over part of its length as a tube of an expandable Material is formed, is known from DE 43 25 969 C1. The longitudinal extensibility of Hose is different on two opposing sides and the interior of the Hose is einfüllenden with a flowable medium under pressure into the tube Pressure source.

A laparoscopic instrument of the aforementioned kind is known from US 6,645,218 B1. The bendable portion of the shank is designed to be elastic, whereby from the top the shank out a number of wedge-shaped slots and from the bottom Shaft arranged a number of between each of the outgoing slots of the top wedge-shaped slots out. From one arranged on the handle actuator go two mutually parallel traction elements from which about the Shank extend to a distal to the bendable section located attachment site. In bendable section, these pull elements of the wedge-shaped through slots spaced portions of the shaft out, which thus as a guide bracket for the tension elements can be considered. The lateral stiffness of the shaft of the instrument in its bendable portion is relatively low.

Object of the invention is to provide an improved laparoscopic instrument of the aforementioned provide kind. According to the invention this is achieved by a laparoscopic instrument with the features of claim 1.

Due to the inventive arrangement in which over the bendable section a extending leaf spring, a high flexural rigidity is achieved in the lateral direction, ie, in a Direction to the plane in which the shaft is perpendicular in its curved state. It can thereby a very good power transmission in this lateral direction can be achieved, thereby For example, a blunt dissection is facilitated.

The invention provides a very cost-effective manufacture of the instrument will allow further. The instrument can be, inter alia, designed as a disposable instrument, so cleaning problems account for and achieved a reduced risk of infection can.

An inventive instrument can be formed in a manner further wherein a residue-free cleaning is made possible. Here, the bendable section is advantageously surrounded by an outer encasing tube which extends preferably over the entire extending length of the shaft.

In a preferred embodiment of the invention a molding of plastics material is present, extending across the bendable portion and having the guide bracket, successive guide brackets respectively by connecting portions of are molded part connected to the free ends of the legs of the U-shaped guide bracket are connected. The leaf spring here runs between the legs of the guide bracket.

Preferably, the bendable portion with a silicone on is the length of the curvable Section poured smooth outer contour, the formation of a cylindrical shell Outer contour is particularly preferred. It may thus, in particular with the preferably used outer encasing, an at least straight state the bendable portion can be achieved substantially smooth outer surface.

Further advantages and details of the invention are hereinafter with reference to the accompanying Drawing explained. Therein:<dl tsize="15" compact="compact"><dt>Fig. 1</dt><dd>a longitudinal section through an embodiment of an inventive laparoscopic Instruments;</dd><dt>FIG. 2</dt><dd>an enlarged detail of Fig. 1;</dd><dt>Fig. 3</dt><dd>a cross section along the line AA of Fig. 2;</dd><dt>Fig. 4</dt><dd>a front part of the stem (without the buffer tube and the silicone sealing compound) in a perspective view;</dd><dt>Fig. 5</dt><dd>a perspective view of the molded part;</dd><dt>Fig. 6, 7 and 8</dt><dd>a bottom view, side view and a top view of the molding.</dd></dl>

One embodiment of a laparoscopic instrument of the invention is in the FIG. FIG. The instrument has a handle 1, a fixed to the handle And a shank 2 arranged at the distal end of the shaft 2 working head 3. The shaft 2 includes a distal, bendable section 4, of the in between a straight position, is shown Fig. 1 in solid lines, and a curved position, which in Fig. 1 indicated by dashed lines, is adjustable. The bendable portion 4 is distal the longitudinal center of the shaft 2, preferably adjacent to one of the operating head 3 area, the distance of the bendable portion 4 from the operating head 3 advantageously less than half the length of the curvable portion 4. To adjust the Curvature of the bendable portion 4 is a arranged in the region of the handle 1 Actuator 5, which in the illustrated embodiment of a the handle 1 pivotally mounted actuating lever is formed.

The proximal portion of the shaft 2 is formed by a tube 6 with its proximal End portion protrudes into a bore in the handle 1 and is fixed in this, for example, is glued. At the distal end of the tube 6 the bendable portion 4 is fixed, for example, glued.

In order to adjust the curvature of the bendable portion 4 is further a pulling element 7, that of a wire or cable is formed (consisting of several strands). The Pulling element 7 extends from the region of the handle 1 to about 4 and the curvable portion is mounted on the distal side of the curvable portion to the shank second On the page the handle 1 is lying end the tension element 7 attached to the actuator. 5

About the bendable section 4, a plurality of longitudinally bendable portion 4 spaced arranged guide handle. 8 This guide bracket 8 are in embodiment shown parts of a molded article 9 (see. Fig. 5 to 8). successive Guide bracket 8 are each formed by a connecting portion 10 of the molding 9 with each other connected. The leads 8 are in cross-section of the shaft 2 (see. Fig. 3) is U-shaped formed and have two legs 8a, 8b, connected to each other through an arc portion are connected. The connecting portions 10 are provided on the remote from the bow section Ends of the legs 8a, 8b integrally formed. Here, it is the region of a guide stirrup 8 each an opening 11 released in the connecting portions 10, whereby the flexibility of the The molding is increased. 9

At its proximal end, the molded part 9 an insertion 12 for plugging and gluing on the tube. 6 Distal of the shunting rings 8 and connecting portions 10 formed section (which coincides with the curvable portion 4 of the shaft 2) includes a mounting portion 13, in which the pulling element 7 on the shaft 2 is fixed. The attachment portion 13 is appropriately trained and sufficiently stable for fixing of the pulling element 7 are used, the two passage openings 14, 15 through which is the tension element performed 7 and this bent, wherein it further in the Sequence can be glued.

Distally connects to the attachment portion 13 of the operating head 3, which in this embodiment is thus formed integrally with the molded part. 9 The working head 3 represents the on the (further described below) outer encasing 24 of the protruding portion Molding 9. The operating head 3 is connected to a extending from one side of the operating head 3 Slot 17 which initially tapers and then a taper to the having enlarged portion 17a. is the frontal or distal end 18 of the operating head 3 formed rounded. With the operating head 3 can blunt dissection be performed.

About the bendable portion 4 extends further a leaf spring 19, which in the unloaded State (ie, without external forces acting) a longitudinally straight course owns. The flat, sheet-like shape, a high flexural rigidity in the lateral direction achieved, ie in a direction perpendicular to the plane in which the shaft 2 is curved in its State is. And there is this lateral bending stiffness in both the curved as well as straight or stretched condition of the shaft 2. It can thus very good power transmission can be achieved in this lateral direction, whereby, for example, a blunt dissection is facilitated.

The flexural rigidity in the direction of the curvature (ie in the upward direction starting from stretched condition in Fig. 1) depends on the spring force of the leaf spring 19. Because of Actuator 5 a very large power transmission is reached, the leaf spring may 19 be interpreted accordingly stiff, so that a relatively high bending stiffness in this Direction is achieved. In the opposite direction (in Fig. 1 downwards) results in a high flexural strength by the holding force of the tension member. 7

The leaf spring 19 is mounted immovably in the axial direction of the shaft.

The leaf spring 19 runs in the illustrated embodiment between the legs 8a, 8b of Guide bracket, being in the region between two guide brackets 8 on the guide brackets 8-facing side of the connecting portions 10 extends. The width of the leaf spring 19 in this case corresponds to the distance between the legs 8a, 8b and the leaf spring 19 is against a withdrawal of the connecting portions 10 by steps of the legs 8a, 8b secured with a small clearance.

In the distal end portion of the leaf spring 19 is adhered to the mounting portion thirteenth Of the proximal end portion extends below a ridge 20 of the insertion section 12 of the molding 9 and stands above the molding 9 proximal something before.

A respective guide bracket 8 limits together with the leaf spring 19 a channel 21, through which the tension element 7 runs.

About the length of the bendable portion 4 is the tension element 7 of a bendable Sliding tube 22 surrounded, which is preferably formed of a Teflon tube to the sliding friction the tension element 7 lower.

Once the leaf spring 19 has been inserted into the molded part 9 and bonded thereto and the pulling element 7 are mounted in the through openings 14, 15 and with deferred Slider 22 passes through the channels 21, these parts with a casting compound, poured preferably silicone, with the parts inserted in a corresponding shape will. It is thereby a part with a smooth outer contour between the working head 3 and the insertion portion 12 is formed, which is preferably a cylindrical casing is. This part includes the bendable portion 4 and extends along the length of Molding 9, except for the operating head 3 and the insertion section 12. The sealing compound 23 is shown only in FIG. 3 for clarity.

As a result, the poured part is glued in the pipe. 6 is a further consequence a heat shrink tube over the length of the shaft 2 turned up, the shrunk in the sequence is, thus, an outer tubular sheath 24 with apparent from FIGS. 1 to 3 Form results. This buffer tube 24 has at least in the straight state of the bendable Portion 4 over the entire length of the shaft 2 has a substantially smooth outer Surface and includes the shaft 2 against the penetration of liquids from. Through this hermetically sealed design of the shaft 2 is a residue-free cleaning of the Instruments allows after an operation. By substantially smooth formation the outer surface of the buffer tube 24 is this cleaning even easier.

In order to fix a set pivot position of the actuator 5 and thus a set curvature of the bendable portion 4 is the actuator 5 cooperating latch means available. This includes a pivotable latching part 25, which is provided with a co-operating with the actuating member 5 toothing. A spring 26 which is gearing up to a locking element of the actuator 5 pressed. snaps With the swiveling of the actuator 5 in the direction of arrow 27 the catch element in the corresponding tooth of the teeth of the locking portion 25th latching can by a manual pivoting of the latching member 25 in the direction of arrow 28 in turn be solved.

At a pivoting of the actuating member 5 in the direction of arrow 27, the tension member is 7 in the direction of the arrow 29, the bendable portion 4 by overcoming the restoring force of the leaf spring 19 is increasingly curved. The curvature of the bendable portion 4 is in this case between the straight position and the maximum curved Position adjustable. In the maximum curved position, in a Instrument according to the invention, an angle 30 of the swiveling of the workhead 3 more than 90 ° can be achieved, said angle of over 110 ° can be achieved in practice.

In the curved state of the bendable portion acting on the tension element a force in Towards a withdrawal of the tension element of the leaf spring 19. The guide bracket 8 is limited such withdrawal of the tension member 7 opposite the leaf spring 19th In shown Embodiment, the tension element of the leaf spring 19 in the straight and in curved state on the curvable portion is substantially the same distance.

The mold part 9 is made of a plastic material, which on the one hand, a sufficient having flexibility to be bent without damage can, on the other hand has sufficient strength to the force exerted by the pulling element 7 forces prior to hold, for example, polysulfone. The buffer tube 24, for example, by a PTFE heat shrink tubing are formed. Instead of teflon, some other medically approved soft plastic material can be used. The leaf spring 19, for example, made of stainless steel. The tension member 7, for example, of a metal wire or metal cable formed.

With an instrument according to the invention can advantageously blunt dissection be carried out, said fabric layers are separated from each other. With the working head 3 may in this case be bypassed structures inside the body. For example, hollow organs or vessels, for which purpose the curvature or bending of the bendable portion 4 is set accordingly. With the operating head 3 can further example Objects, such as threads or implants to hollow organs or vessels are pulled around. For example, an instrument according to the invention in the transplantation of an Gastric band be used advantageously.

Various modifications of the described embodiment of the invention are conceivable and possible without the scope of the invention to leave. It would, for example, conceivable and possible, the guide bracket set directly on the leaf spring 19, a over the length of the bendable portion 4 extending molding could also be omitted. For example, the guide bracket 8 could on the leaf spring 19 with the two ends their legs be welded. The leads 8 could this z. B. from a curved Metal wire are formed.

Furthermore, it would also be conceivable and possible to omit the sealing compound of silicone when a buffer tube is inserted from a sufficiently stable material, so not to strong unevennesses on the outside of the buffer tube shown which operation using the affect the instrument. The buffer tube could be considered in a different way be formed by a shrink tube. Conceivable and feasible would also be, the buffer tube omit and provide only a grout that of the outer surface Shaft in the curvable portion forms, this in particular if the instrument only as a disposable instrument is used.

The leaf spring 19 could, for example, also consist of a shape memory alloy (a Material with so-called shape memory) exist. The restoring properties of such shape-memory alloys are also referred to as "pseudo elastic". For example could be used here nickel-titanium alloys.

Other actuators as pivotable handles are conceivable and possible. So could be present, for example, a rotatably mounted nut, in which a thread compared with a twist secured threaded rod protrudes, at the fixed the tension element 7 is. In principle, there could be also more than a single tension member. The guide bracket 8 could be closed also in the region between the pulling element 7 and the leaf spring 19 be formed, whereby separate channels for carrying out the tensile element 7 and the leaf spring 19 could be formed.

legend TO THE REFERENCE NUMBERS:

<dl tsize="3" compact="compact"><dt>1</dt><dd>handle</dd><dt>2</dt><dd>shaft</dd><dt>3</dt><dd>working head</dd><dt>4</dt><dd>krümmbarer section</dd><dt>5</dt><dd>actuator</dd><dt>6</dt><dd>pipe</dd><dt>7</dt><dd>tension element</dd><dt>8th</dt><dd>guide bracket</dd><dt>8a</dt><dd>leg</dd><dt>8b</dt><dd>leg</dd><dt>9</dt><dd>molding</dd><dt>10</dt><dd>connecting portion</dd><dt>11</dt><dd>opening</dd><dt>12</dt><dd>insertion</dd><dt>13</dt><dd>attachment portion</dd><dt>14</dt><dd>Passage opening</dd><dt>15</dt><dd>Passage opening</dd><dt>17</dt><dd>slot</dd><dt>17a</dt><dd>enlarged portion</dd><dt>18</dt><dd>distal end</dd><dt>19</dt><dd>leaf spring</dd><dt>20</dt><dd>web</dd><dt>21</dt><dd>channel</dd><dt>22</dt><dd>slider</dd><dt>23</dt><dd>potting compound</dd><dt>24</dt><dd>encasing</dd><dt>25</dt><dd>latching part</dd><dt>26</dt><dd>feather</dd><dt>27</dt><dd>arrow</dd><dt>28</dt><dd>arrow</dd><dt>29</dt><dd>arrow</dd><dt>30</dt><dd>angle</dd></dl>