Instrument for cutting body tissue

An instrument for cutting body tissue has an instrument shaft, A blade, is adjacent to a distal end of the instrument shaft and can be folded out with respect to a longitudinal axis of the shaft and can be rotated about the longitudinal axis. An operating part is at a proximal end of the instrument shaft. A proximal end of the blade directed toward the operating part can be pivoted laterally out away from the longitudinal axis about an end of the blade that faces away from the proximal end and that is distally articulated at an articulation point. A tissue stop is arranged at the distal end of the instrument shaft. The tissue stop can be brought into an active position in which a stop surface facing the blade in the proximal direction has a specified fixed distance from the articulation point.

BACKGROUND

Field of the Invention

The invention relates to an instrument for cutting body tissue, comprisingan instrument shaft,a blade, which is arranged adjacent to the distal end of the instrument shaft and can be folded out with respect to a longitudinal axis of the shaft and can be rotated about the longitudinal axis, andan operating part arranged at the proximal end of the instrument shaft.

Description of the Related Art

From Banerjee C., Kaiser N., Hatzmann W., Reiss G., Schmitz J., Hellmich M., Noé G. “Reduktion der Spottingrate nach laparoskopischer suprazervikaler Hysterektomie” (Lower Spotting Rates after Laparoscopic Supracervical Hysterectomy) Geburtsh Frauenheilk 2010; 70: 798-802 it is a known procedure to perform deep-cone excision of the cervical canal endoscopically and additionally to coagulate the remaining portion of the cervical canal by applying an electric current. The conical endoscopic excavation of the cervical stump allows better detection of endometrioid cells in the isthmic and cervical region than coagulation alone. In this procedure, suprapubic access to the cervical canal by means of a trocar or trocar sleeve offers certain advantages compared to vaginal access to the cervical canal, such as a low spotting rate.

From US 2012/0143209 A1, a medical instrument for a laparoscopic supracervical hysterectomy (LASH) is known. The known instrument for cutting body tissue comprises an instrument shaft, a blade, which is arranged adjacent to the distal end of the instrument shaft and which can be folded out or pivoted out with respect to a longitudinal axis of the shaft and can be rotated about the longitudinal axis, and an operating part arranged at the proximal end of the instrument shaft.

The disadvantage here is that this instrument is not suitable for suprapubic access to the cervical canal via a known laparoscopic trocar or trocar sleeve.

Furthermore, from US 2006/09490083 A1 a tissue stop arranged at a distal shaft end is known, which is designed as a four lever parallelogram that can be pivoted out laterally around an axis arranged transverse to the longitudinal axis, in such a way that two each of the levers can be folded out laterally transverse to the longitudinal axis.

From U.S. Pat. No. 6,641,581 B2 an instrument for cutting body tissue is known that comprises an instrument shaft with a longitudinally displaceable and rotatable electrode array protruding at the distal end thereof and with a curved arm protruding laterally at the distal end thereof, said arm extending a cutting electrode.

The disadvantage here is that, due to the rigid laterally protruding arm, the distal end of the instrument shaft or the electrode array respectively, is not well-suited for insertion through a trocar sleeve into a body cavity with tissue to be cut. Another disadvantage is that this instrument does not comprise a tissue stop.

From US 2004/002701 A1 a shaft end with two jaws is known that can be folded out laterally. These jaws are designed as an ultrasound device emitting in distal direction. Therefore, a person skilled in the art would not consider the replacement of the mechanical tissue stop from D1 with the jaws known from D4 as common practice.

The object of the present invention is to provide an instrument that is particularly suited for the cone-shaped excavation of the cervix and that allows suprapubic access to the cervix by means of a laparoscopic or trocar sleeve.

SUMMARY OF THE INVENTION

An instrument for cutting body tissue has an instrument shaft. A blade is arranged at a distal end of the instrument shaft and can be folded out with respect to a longitudinal axis of the shaft and can be rotated about the longitudinal axis. An operating part is at a proximal end of the instrument shaft. The distal end of the instrument shaft can be inserted into a body cavity with tissue to be cut, through a trocar sleeve. A proximal end of the blade directed toward the operating part can be laterally pivoted out away from the longitudinal axis about an end of the blade that faces away from the proximal end and that is distally articulated to an articulation point An outer sleeve rotatable about the longitudinal axis is arranged at the distal end of the instrument shaft, said outer sleeve having a lateral opening transverse to its longitudinal direction from which the blade can be pivoted out.

By means of the laterally pivotable or foldable (pivotable and foldable are used synonymously in the following) blade which, for example, can be designed as a knife or as a (high frequency) cutting electrode, and the tissue stop which can be brought into an active position with a predetermined fixed distance to the articulation point, the instrument shaft, i.e., the distal end thereof, can, in a non-active starting position, e.g., with the tissue stop not unfolded, be inserted easily into a body cavity with tissue to be cut, e.g. a cervical canal, via a suitable conventional trocar sleeve. In the process, the tissue stop can be folded out for example laterally into its active position and the instrument can be locked in its position.

By means of the tissue stop, the intended cutting position of the blade can thus be fixed or ensured.

The blade can be folded out or pivoted out from the lateral opening of the rotatable outer sleeve into an intended position and can be turned by rotating the blade around the longitudinal axis of the instrument shaft so that the surrounding tissue is cut out in a conical shape.

According to a preferred embodiment of the invention, the fixed distance between the stop surface of the tissue stop in its active position (e.g. at the wall of the Portio vaginalis) and the articulation point of the blade is greater than 1.5 mm. As a result, for example, in the case of so-called LASH conization, this will guarantee the reliable removal of the mucosa in the cervical canal. A fixed distance of about 4 to 20 mm, and preferably 12 mm, has proved to be especially appropriate. To adapt to anatomical conditions, greater or smaller distances are also possible.

According to a further preferred embodiment of the invention, the tissue stop folds out into its active position about a first transverse axis which is arranged at the distal end of the instrument shaft. The tissue stop can thus be folded out from the longitudinal axis into its active position from a starting position arranged in the longitudinal direction. In the active position, the rear, i.e. proximally directed stop surface can have an angle of preferably 90 degrees relative to the longitudinal axis. However, intermediate positions and angles greater than 90 degrees are possible as well.

According to a preferred embodiment of the invention, the blade has a cutting edge on at least one of its two longitudinal sides that extend parallel to the longitudinal axis.

With the sharp cutting edge, the blade forms a knife that is rotatable around the longitudinal axis and with which a tissue cone can be mechanically excised. By means of a coagulation electrode or laser radiation, the cut tissue surface can be coagulated.

According to a further preferred embodiment of the invention, the instrument shaft comprises an outer shaft tube whose distal end is connected to the outer sleeve, and wherein an inner shaft tube is arranged in the outer shaft tube. Between the outer sleeve and the inner shaft tube an inner sleeve is arranged having the blade on its proximal end face. The inner sleeve is thus rotatable around the inner shaft tube together with the outer sleeve and the outer shaft tube. Furthermore, the outer shaft tube with the outer sleeve is longitudinally displaceable with respect to the inner shaft tube and the inner sleeve.

Insofar as the blade is spring-mounted at its distally articulated end, the lateral opening of the outer sleeve can be brought into alignment with the proximal end of the blade by displacing the outer shaft tube with the outer sleeve, so that, due to the spring effect, the blade's proximal end folds out or pivots out of the lateral opening. By retracting the outer shaft tube with the outer sleeve, the articulated end of the blade is covered and the blade is folded into the opening again. The proximal end of the blade is preferably designed as a free end, but can in principle also be connected to a longitudinally displaceable joint arrangement or the like.

According to a further preferred embodiment of the invention, the inner sleeve and the blade are formed from a shape memory alloy at least in the region of their articulation point. The shape memory alloy is designed in such a way that a predetermined fully extended position is the preferred position, with the free end of the blade being “folded in” by covering it with the outer sleeve, and with the free end, upon release, folding out into its predetermined extended position.

According to a further preferred embodiment of the invention, a longitudinally displaceable first operating element is arranged on the operating part, and the outer shaft tube with the outer sleeve is displaceable in order to actuate the blade, i.e., to fold the blade out or in. The operating element is lockable in different locking positions. By locking the first operating element, the blade can be fixed between a retracted and fully extended position at different angles relative to the longitudinal axis.

According to a further embodiment of the invention, a second rotatable operating element is arranged on the operating part and with it the outer shaft tube with the blade folded out from the outer sleeve can be rotated around the longitudinal axis of the instrument shaft. By rotating the blade around the longitudinal axis, a tapered or cone-shaped tissue portion can thus be easily excised.

According to a further preferred embodiment of the invention, the blade is designed as an electrode. By connecting the blade to an active terminal of a high-frequency generator, while connecting the patient to a large-surface neutral electrode, an electrosurgical cut can be performed. Furthermore, with the flat side of the blade the contacted tissue can be coagulated.

Instead of a large-surface neutral electrode, the tissue stop may also be designed as an electrode which is connected to the high-frequency generator, with the blade and the tissue stop forming a bipolar electrode pair.

According to a further preferred embodiment of the invention, the tissue stop comprises two jaws with mirror-symmetrically designed guide grooves arranged in a U-shaped, i.e. forked, mounting bracket at the distal end of the instrument shaft. The jaws with their guide grooves are pivotable opposite to each other around a first transverse axis arranged in the mounting bracket transversely to the longitudinal axis, with the jaws being connected at their proximal ends, via a second transverse axis arranged parallel to the first transverse axis, to a distal end of a longitudinally displaceable lifting rod positioned in the inner shaft tube. By longitudinally displacing the lifting rod in the distal direction, the second transverse axis is thus moved in the direction of the fixed first transverse axis so that the jaws, similar to the jaws of forceps, open outward in the radial direction and close by moving the lifting rod in the proximal direction.

According to a further preferred embodiment of the invention, in the operating part the proximal end of the lifting rod facing away from its distal end is operatively connected to a third operating element. The tissue stop can thus be locked in different locking positions via the third operating element.

The instrument according to the invention for cutting body tissue is particularly suited as a laparoscopic instrument for cutting and/or coagulating the inner portio.

With both the blade and tissue stop retracted, i.e. in a starting position, the instrument can be inserted into the cervical canal through a trocar sleeve and further through the portio. The tissue stop can be folded out and pulled against the portio. After unfolding the blade and activating the electric current, the cutting is performed by rotating the outer shaft tube together with the outer sleeve and the inner sleeve, while the tissue stop with the inner shaft tube does not co-rotate. After folding/pivoting the blade and the tissue stop back in, the instrument can be extracted from the trocar sleeve. For example, the blade can be pivoted at an angle between 0 and 45°. Thus, a precise adjustment of the tissue ablation can be ensured. The precise positioning is supported by the rear stop of the tissue stop at the portio entrance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Identical reference symbols in the figures indicate identical or analogous elements. The following description refers to all Figures, unless exclusive reference is given to a specific Figure.

An instrument1for cutting body tissue comprises primarily an instrument shaft2, a blade3, a tissue stop4and an operating part5.

At a distal end6of the instrument shaft2facing away from the surgeon, an outer sleeve8is arranged which can be rotated around a longitudinal axis7of the instrument shaft2, said outer sleeve8having a lateral opening, i.e. a rectangular aperture, namely a kind of window, transverse to its longitudinal axis. Facing the surgeon, at its proximal end10the instrument shaft2possesses the operating part5. The instrument shaft2consists of an outer shaft tube11and an inner shaft tube12which is movable (longitudinally displaceable and rotatable) within the outer shaft tube11.

For cleaning purposes, the distal end6of the outer shaft tube11is detachably connected to the proximal end10of the outer sleeve8by a connecting thread. Between the outer sleeve8and the inner shaft tube12, an inner sleeve13is arranged, which, at its proximal end face, merges into the blade3. When the lateral opening9is aligned with the blade3, the blade3, which is articulated at its distal end to the inner sleeve13, folds out through the lateral opening9with its proximally free end14and forms a maximum pivot angle15of, for example, 45° relative to the longitudinal axis7.

The blade3possesses a cutting edge18on both of its longitudinal sides16,17extending parallel to the longitudinal axis7. The inner sleeve13and the blade3connected thereto are made of a shape memory alloy with the maximum pivot angle15being imprinted at the articulation point19. Shape memory alloys (SMA), which are also referred to as memory metals are known to those skilled in the art. These materials exhibit the phenomenon that they are seemingly able to “remember” their original shape even after considerable deformation. Suitable materials include:NiTi (nickel-titanium; nitinol)CuZn (copper-zinc)CuZnAl (copper-zinc-aluminum)CuAlNi (copper-aluminum-nickel)FeNiAl (iron-nickel-alumnium).

The inner sleeve13together with the outer sleeve8and the outer shaft tube11is rotatable around the inner shaft tube12. The outer shaft tube11with the outer sleeve8is longitudinally displaceable with respect to the inner shaft tube12and the inner sleeve13. The longitudinal displacement between the outer sleeve8and the inner sleeve13causes the folding in and folding out of the blade3from the lateral opening9of the outer sleeve8.

Via a longitudinally displaceable first operating element20arranged on the operating part5, said operating element20being connected to the proximal end21of the outer shaft tube11, the outer sleeve8can be moved in the longitudinal direction relative to the inner sleeve13with the blade3so that the blade3is covered at its articulation point19and thus folded in/pivoted in, or it is released and thus folded out/pivoted out.

The operating part5comprises a second operating element22which is mounted rotatably about the longitudinal axis7on a main component23of the operating part5, which is firmly attached to the inner shaft tube12. In the second operating element22of the operating part5, the first operating element20is longitudinally displaceable and lockable in different locking positions by means of a locking device24. By rotating the second operating element22, the outer shaft tube11with the outer sleeve8and the first operating element20can be rotated around the inner shaft tube12. By retracting the first operating element20in the proximal direction, the blade3folds in. By moving the first operating element20in the distal direction, the blade folds out/pivots out, depending on how much the lateral opening with the blade is covered. Different locking positions of the first operating element20thus result in different pivot angles15of the blade3.

As an extension of the instrument shaft2, the tissue stop4is arranged at the distal end6thereof. The tissue stop4consists of two jaws25,26that are pivotable opposite to each other and arranged in a U-shaped mounting bracket27. The jaws25,26each have a guide groove28,29. The two guide grooves28,29are designed mirror-symmetrically to one another. The jaws25,26with their guide grooves28,29are thus pivotable opposite to each other around a first transverse axis30arranged transversely to the longitudinal axis7in the mounting bracket27. The jaws25,26are connected at their proximal ends via a second transverse axis31with the distal end32of a lifting rod33which is longitudinally displaceable in the inner shaft tube12. At its proximal end34, the lifting rod is operatively connected to a third operating element35in the operating part5.

The third operating element35is designed as a wheel37with a radially arranged operating lever38, said wheel37being rotatable around a third transverse axis36which is arranged parallel to the first transverse axis30and the second transverse axis31. The wheel37is connected to the proximal end34of the lifting rod33via a laterally and transversely extending groove39. With a partial rotation of the wheel37, the tissue stop4can be adjusted via the lifting rod33between a starting position with retracted jaws25,26and a fully extended position of the jaws25,26. The end and intermediate positions can be fixed by means of a second locking device40which is arranged between the third operating element35and the operating part5. For this purpose, the wheel37comprises latching grooves41on its circumference, into which a spring-mounted latching element42can engage. The tissue stop4can thus be locked in different locking positions or extended positions.

With their outer edges facing in the folding-out direction the jaws25,26form the stop surfaces47,48which, in their active position, have a fold-out angle49of, for example, 90° relative to the longitudinal axis7and a fixed distance50of >1.5 mm relative to the articulation point19. In the exemplary embodiments the fixed distance50is about 12 mm.

In the exemplary embodiments, the blade3is designed as an electrode which is conductively connected to the operating part5via a plug contact43. The plug contact43can be connected to a female connector44of an electrode cable45leading to an electrosurgical unit (not illustrated), namely a high-frequency generator.

Of course, the embodiments discussed in the specific description and shown in the Figures are merely illustrative exemplary embodiments of the present invention. In the light of the present disclosure a person skilled in the art has a broad spectrum of optional variations available.

In particular, the tissue stop4, which is electrically insulated from the blade3, can be used as a second electrode so that the tissue stop4and the blade3form a bipolar electrode pair which can be connected to the high-frequency generator or electrosurgical unit (not illustrated).

LIST OF REFERENCE NUMBERS