WO2013064576A1

WO2013064576A1 - Hf surgical resection instrument having a device for checking the opening width of a loop

Info

Publication number: WO2013064576A1
Application number: PCT/EP2012/071628
Authority: WO
Inventors: Günter Farin
Original assignee: Endox Feinwerktechnik Gmbh
Priority date: 2011-11-03
Filing date: 2012-10-31
Publication date: 2013-05-10
Also published as: DE102011085720A1

Abstract

An RF surgical resection loop comprises at least one first electrically non-insulated loop section and a second electrically insulated loop section. The electrically non-insulated loop section transfers current into the tissue, whereas the electrically insulated loop section is only used for mechanical fixing and guidance. At least one of the loop sections is adjustable in its length by a manipulation wire which is guided in a catheter. A scale and/or display apparatus which displays and/or signals the opening width of the loop is disposed at a proximal end of the catheter.

Description

HF surgical resection instrument having a device for checking the opening width of a loop

Field of the invention The invention relates to an RF surgical resection instrument with resection loops as are used for example for the resection of intestinal polyps, and instruments and apparatuses for the operation of such resection instruments. The invention further relates to a manipulation handle for such instruments.

Description of the related art RF surgical resection instruments with resection loops for removing pathological tissue, especially adenoma of the mucosa and submucosa (hereinafter referred to as lesions) that grow in a flat or polyp-like manner in hollow organs of the gastrointestinal tract, are known for example from DE 2 132 808. These instruments comprise a flexible catheter with a proximal and distal end, an RF surgical resec- tion loop which is pushed out of the distal end of the catheter by means of a manipulation wire which is displaceable in the catheter in the axial direction and can be retracted into said distal end. Furthermore, a manipulation handle is provided at the proximal end of the catheter, by means of which the manipulation wire can be moved in a forward and rearward direction. As a result of the movement of the manipulation wire, the loop can be opened or closed. By feeding radio- frequency current (RF current) from an RF surgical generator through the loop into the tissue or by forming electrical arcs between the loop and the tissue said tissue can be cut or severed by RF surgery.

WO 2011/012616 A2 discloses an asymmetrical loop. It comprises a passive, electrically insulated section and an active, electrically non-insulated section. A cutting current can only flow into the tissue through the electrically non- insulated section.

A relevant problem in the resection loops as known from the state of the art is that the loop is only badly visible during an incision or resection phase. As a re- suit, a larger loop in particular is only partially visible and/or in a distorted manner through an endoscope. Especially when a part of the loop is covered during the incision by the tissue to be cut such as a polyp, it can no longer be seen through the endoscope. Consequently, the loop opening and therefore also the progress of the incision or resection are hardly visible. The problem increases with the size of the polyps or lesions to be removed, especially when they need to be removed in one piece. It is a complicating factor that especially large polyps or lesions need to be injected in the submucosa for example with a physiological NaCI solution prior to the application of the loop, and will therefore become even larger than they would have been without the injection.

Summary of the invention

The invention is based on the object of providing an RF surgical resection instrument with a loop and an apparatus which allows stating the opening state or the opening width of an RF surgical loop and thereby indicating to the surgeon the opening state or progress of an incision or resection. Furthermore, a respective manipulation handle shall be provided with which the loop can be controlled in a purposeful manner.

This object is achieved by an apparatus according to claim 1. Advantageous embodiments of the invention are provided in the dependent claims. The invention is based on extensive technical and scientific examinations of a large number of different RF surgical loops and surgeries performed with said loops. The loop opening can principally be changed by actuating the manipulation wire. Nevertheless, most RF surgical loops known from the state of the art do not provide any clear connection respectively correlation between the position of the manipulation wire and the loop opening. Right after the loop has per- formed the first RF surgical resection and the material of the loop has heated up strongly, it will be relatively soft and assume non-reproducible random shapes after being pushed out of the distal end.

Measures or scales are provided in such instruments at the proximal end of the catheter which indicate the length of displacement of the manipulation wire. However, it does not correlate with the loop opening. Consequently, this indication is rather confusing or even dangerous. It is proposed in this respect for example in Techniques in Therapeutic Endoscopy, 2nd Edition, edited by J.E.

Geenen, D.E. Fleische and J.D. Waye; 1992: 10.2-10.20 concerning the verification of the position of the distal end of the loop in relation to the distal end of the catheter that the position of the slider on the slide rail in which the distal end of the loop is disposed at the distal end of the catheter is marked with a line. This marking fulfils only one single purpose however, which is to enable checking from which position of the slide on the slide rail the distal end of the loop enters into the distal end of the catheter. If this position is reached during resection, one can assume that the polyp or the mucosa area to be severed has been severed completely from the organ wall. Subsequent checking is also not possible with this system.

The invention is especially based on the finding that there will be a sufficiently good correlation between the axial movement of the manipulation wire in the catheter and the resulting change in the shape and opening width of the loop or the area comprised by the loop only in the case of asymmetrical loops as disclosed in WO 2011/012616 A2 for example. In the case of such a loop, a long loop section consists of a spring-elastic material, so that it will open the loop with a relatively large loop opening. Moreover, the long loop section of this asymmetric loop is electrically insulated and will therefore not be heated by the very hot electrical arcs present in RF surgical cutting, so that the spring-elastic properties of the material of this loop section will be maintained during incision and even after several resection.

In accordance with the invention, a measuring and/or display apparatus is preferably arranged at the proximal end of the catheter of such a loop, which measuring and/or display apparatus determines or indicates the axial position of the manipulation wire relative to the catheter. Principally, such a display device could also be attached at any other point within the catheter, e.g. directly at the distal end close to the loop. It is especially advantageous if such a display apparatus is attached to a manipulation handle or is at least connected with said handle. The display apparatus is preferably a scale or measure indicating a value which offers a clear connection with the loop opening. The loop opening shall preferably mean in this case the area comprised by the loop. Additionally or alternatively, a circular diameter calculated from the area encompassed by the loop can also be indicated. The diameter determined in this manner is suitable to objectify or specify the diameter of polyps or lesions which up until now has been stated in a substantially undefined manner. Similarly, a length and/or a width and/or other dimensions of specific groups could also be stated. One or several of the values listed here can be indicated.

Alternatively and/or additionally, a sensor can also be provided which transmits its measured values via a displacement of the manipulation wire relative to the catheter to an external control and/or evaluation unit. Such a control unit can be arranged for example in or on a radio-frequency surgical generator which supplies the loop with radio-frequency current. Alternatively and/or additionally, a display unit such as a display for example can be provided which displays or indicates the opening of the loop in a numerical and/or graphical manner. The dis- play can occur in this case for example as numbers in units of length such as centimeters, millimeters or even inches. The size of the open loop can also be illustrated symbolically. It is especially advantageous if a loop is displayed graphically in a view in which the size of the opening is recognizable. It is also possible to mix the loop into a video image which is transmitted by the endoscope. The illustration of a grid and/or a scale together with the loop is especially advantageous in order to illustrate the ratio of dimensions.

An apparatus in accordance with the invention can also be used as a measuring apparatus. It can be used for determining lines and/or areas in the interior of a body or a cavity. The loop can be pulled around a lesion or a specific object such as a polyp for example and the respective area or other dimension of the polyp can be displayed. Lengths can also be estimated by applying the loop to objects.

Especially precise results are obtained if during the determination of the measured values the loop remains in a mechanically unloaded state, i.e. it does not exert any pressure on the tissue. As a result of the state, the loop assumes the shape provided by its mechanical construction and its geometry as a function of the displacement of the manipulation wire. When the loop is loaded, i.e. it exerts pressure on the tissue, it will be deformed according to the shape of the tissue. It is therefore useful if for the purpose of measuring the loop geometry that a force-free state is produced by a respective incision, i.e. by respective supply of current to the loop, and/or if at least a force-free state is determined and the position of the manipulation wire is measured in such a force-free state. It is especially advantageous if a force sensor or at least a force indicator is provided for this purpose. It is preferably arranged on the catheter, especially at its proximal end. As a result, a measuring device will only perform a measurement when the force sensor is indicated that the force has fallen beneath a specific threshold. There could also be an indication in connection with the display if a measurement is made under force in that said measurement is imprecise as a result of the high force on the loop. Furthermore, error estimation could occur on the basis of the force on the loop and a force-dependent tolerance value of the measurement of the loop geometry could be indicated. Furthermore, an incision could be guided by intelligent control of the loop, its movement or by control of an RF surgical generator connected to the loop in such a way that a specific force-free state is reached at least briefly during an incision and the loop geometry is determined in this state.

It is especially advantageous when a sensor signal of the position sensor of the manipulation wire and/or a sensor signal of the force signal is transmitted to a control unit which is integrated in an RF surgical generator or is connected to such a generator, and said control unit controls the incisions according to said sensors in such a way that there will be a predetermined sequence of the incision such as a reduction in the loop size or the loop cross-section at constant speed. A further object of the invention is an apparatus for controlling an RF surgical generator for supplying an RF surgical resection instrument as disclosed herein.

A further object of the invention is an RF surgical generator for supplying an RF surgical resection instrument as disclosed herein.

A further aspect of the invention is a manipulation handle, which is also generally known as a handle, for actuating an endoscopic instrument and especially a loop. The handle preferably corresponds to the handle as described above and can be produced in the embodiments as described herein. It preferably comprises a first part which is connected with the catheter and a second part which is connected with the manipulation wire. The first part especially preferably comprises a re- leasable connector to the catheter, e.g. a Luer lock. Different catheters can be connected with the manipulation handle in this way. Preferably, the handle also comprises a scale. It is further preferable when the second part is releasably connected with the manipulation wire, e.g. via a clamp. For the purpose of actuating the catheter, the first part of the handle can be pulled away from the second part or be pushed towards the same. As a result of this movement, the manipulation wire will be displaced in the interior of the catheter in the longitudinal direction and will therefore control the loop opening. Furthermore, the first part of the handle can be rotated in relation to the second part. As a result of this rotational movement, the manipulation wire in the interior of the catheter will be twisted in relation to the catheter, leading to a rotation of the loop. For this purpose, the manipulation wire is preferably arranged in an especially torsion- stiffness way in order to transmit the rotational movement with a low amount of hysteresis to the loop.

In an especially preferred manner, at least one of the parts and especially preferably both parts of the manipulation handle are provided with handles of an approximately cylindrical shape. It can also be approximated by a polygon such as a hexagon or an octagon. Similarly, elevations can be provided in the region of the ends of the cylinder in order to obstruct or prevent slipping of the hand. Alternatively or additionally, handle grooves or bulges and other elevations or depressions can additionally also be provided.

The manipulation handle can be used universally. Substantially more precise ro- tation is enabled by the large handle surfaces than would be the case with conventional manipulation handles. Moreover, especially precise displacement is further possible.

Description of Drawings

The invention will be described below by reference to exemplary embodiments shown in the drawings without any limitations to the general inventive ideas, wherein: Fig. 1 shows a detailed view of a handle of an apparatus in accordance with the invention in the extended state;

Fig. 2 shows an embodiment of an RF surgical resection loop;

Fig. 3 shows the loop in a further retracted state;

Fig. 4 shows an endoscopic instrument with an RF surgical resection loop; Fig. 5 shows a handle;

Fig. 6 shows the handle in the state when pushed together; Fig. 7 shows a universal handle;

Fig. 8 shows a conventional, symmetrically opening and closing RF surgical resection loop. Fig. 1 shows a detailed view of a handle 60 according to an embodiment of an apparatus in accordance with the invention in the extended state. The handle 60 comprises a first handle part 61 which is rigidly connected with the proximal end of the catheter, and a second handle part 62 which is connected within the handle with a manipulation wire and therefore allows a displacement of the manipu- lation wire in relation to the catheter. The illustration further shows two scales 63. The bottom one of the two scales shows the area comprised by the loop in cm². The upper one of the two scales shows a circular diameter according to the area in centimeters comprised by the loop. Reading occurs in this case for example at the entrance point of the scales into the first part 61 of the handle. In the illustrated example, the circular loop diameter is smaller than 1 cm and the area comprised of the loop is slightly smaller than 1 cm². Preferably, such scales are determined by measuring the loop and especially the area comprised by the loop at different positions of the handle. Fig. 2 shows an asymmetrically opening and closing RF surgical resection loop 20. This loop comprises a non-insulated loop section 2 and an insulated loop section 3 which is enclosed by insulation 13. The loop sections are preferably made of spring-elastic metallic wire. The non-insulated loop section 2 is fixed to a driver 33. Said driver rests on a stop 37 in the open state of the loop. The insulated loop section 3 is connected with a second driver 32 and the manipulation wire 11. The manipulation wire 11 is guided through a catheter 12. It is further guided through a bore 35 of the driver 33 and can be moved freely in relation to the same within certain limits. The second driver 32 will engage in the first driver 33 only when the manipulation wire 11 has been pulled in to a sufficiently high ex- tent into the catheter, so that the non-insulated loop section 2 is also pulled into the catheter in this way.

A loop width 50 and a loop length 51 are shown for the description of the loop geometry. It is also possible to indicate the entire area comprised by the loop, or a circle whose diameter corresponds to the area enclosed by the loop. Fig. 3 shows a loop according to the preceding drawing, but in a state in which the loop is closed even further.

Fig. 4 shows an endoscopic instrument with an RF surgical resection loop 1 at the distal end of a catheter 12, of the catheter and a handle 60 at the proximal end of the catheter. Fig. 5 shows the complete handle 60 of Fig. 1 with a first handle part 61 which is rigidly connected with the proximal end of the catheter 12, a second handle part 62 that is connected with the manipulation wire and therefore allows a displacement of the manipulation wire in relation to the catheter. The handle is shown in this case in an extended position in which the manipulation wire has been pulled into the catheter in the proximal direction and the loop is conse- quently closed.

Fig. 6 shows the handle of the preceding illustration, but in the state when pushed together, so that the manipulation wire is displaced in the direction of the distal end of catheter, by means of which the loop is opened.

Fig. 7 shows a universal handle. It can be connected with different catheters 12 by means of a preferably releasable connection 64. It comprises a first part 61 which is connected or can become with the catheter and a second part 62 which is connected the manipulation wire. The approximately cylindrical handles of the parts can respectively be gripped by hand very well. By pulling the first part 61 apart in relation to the second part 62 and pushing them together again in the illustrated direction 70, the manipulation wire can be displaced in the catheter and the loop opening can therefore be changed. The manipulation wire can be twisted in relation to the catheter and therefore also the loop by turning the first part 61 in relation to the second part 62 in the illustrated directions of rotation 71. Fig. 8 shows a conventional RF surgical resection loop 7 which opens and closes symmetrically and whose loop wire is relatively flexible and elastic prior to application and is respectively dimensional stable, but which has lost its elasticity and dimensional stability during application as a result of the high temperatures of electric arcs during cutting and therefore can assume a relatively undefined shape. It is not possible in this case to draw conclusions on the shape or area of the loop on the basis of the position of the manipulation wire. List of reference numerals

1 RF-surgical resection loop

2 Electrically non-insulated loop section

3 Electrically insulated loop section

4, 5 Distal ends of the loop sections

7 Conventional, symmetrically opening and closing RF surgical resection loop with flexible wire

9, 10 Proximal ends of the loop sections

11 Manipulation wire

12 Catheter

13 Insulation

20 RF-surgical resection loop

32 Driver for insulated loop section

33 Driver for non-insulated loop section

35 Bore

37 Stop

50 Loop width

51 Loop height

60 Handle

61 Part of handle on catheter

62 Part of handle on manipulation wire

63 Scale

64 Connector

70 Direction of displacement

71 Direction of rotation

Claims

An RF surgical resection instrument, comprising a catheter (12) with a proximal and a distal end, in which a manipulation wire (11) is guided, and a monopolar loop (1, 20) for wrapping around and severing tissue by RF surgery, comprising at least two loop sections (2, 3),

- which are connected with one another at their distal ends (4, 5) or consist of a single unit, with

- one of the two loop sections (2) being electrically conductive on the surface and the other of the loop sections (3) being electrically insulated, and with

- one loop section (3) being connected with the manipulation wire (11) or being extended as a manipulation wire within the catheter, so that the at least one loop section can be pulled through the same into the catheter (12) and can be pushed out of the same, characterized in that

at least one measure and/or scale and/or a sensor is provided at the proximal end of the catheter (12), which is connected with the manipulation wire (11) and which displays and/or signals at least the opening width of the loop.

An RF-surgical resection instrument according to claim 1, characterized in that

the scale displays the area and/or the diameter of a circular area which corresponds to the area encompassed by the loop.

An RF-surgical resection instrument according to claim 1 or 2, characterized in that the scale is attached to a handle which is arranged at the proximal end of the catheter.

4. An RF-surgical resection instrument according to one of the preceding claims, characterized in that

the sensor is an electrical resistor which is integrated in the handle of the instrument and whose resistance value is a function of the position of the manipulation wire relative to the catheter.

5. An RF-surgical resection instrument according to one of the preceding claims, characterized in that

the sensor sends the signals for signaling the opening width of the loop to a separate display device and/or evaluation device.

6. An RF-surgical resection instrument according to one of the preceding claims, characterized in that

the sensor sends the signals for signaling the opening width of the loop to an RF surgical generator.

7. An apparatus for controlling an RF surgical generator for supplying an RF surgical resection instrument according to one of the preceding claims.

8. An RF surgical generator for supplying an RF surgical resection instrument according to one of the claims 1 to 7.

9. A manipulation handle for controlling an RF surgical resection instrument according to one of the claims 1 to 7.

10. A manipulation handle for controlling an RF surgical resection instrument having a catheter (12) and a manipulation wire (11), comprising: - a first part which can be connected with the catheter,

- a second part which can be connected with the manipulation wire, with the first part and the second part having an approximately cylindrical handle.

11. A manipulation handle according to claim 10,

characterized in that

the manipulation handle comprises a scale.

12. A manipulation handle according to claim 10 or 11,

characterized in that

the manipulation handle comprises a sensor.