NL2012071C2 - Industrial or medical tool with steering cables. - Google Patents

Abstract

Instrument provided with cables extending between a first portion and a second portion of the instrument at opposite sides of its longitudinal axis and disposed at predefined angles with respect to said axis, which instrument has one or more sets of cables, each set of cables comprising in combination a first cable running parallel to the longitudinal axis, a second cable running at a first predefined angle with respect to said longitudinal axis, and a third cable running at a second predefined angle with respect to said longitudinal axis and having a sign that is opposite to the sign of the first predefined angle so as to arrange that the second and third cables cross each other. The instrument is preferably a joystick or a surgical instrument, such as a laparoscopic tool.

Description

Industrial or medical tool with steering cables

The invention relates to an instrument provided with cables extending in a predefined area between a first portion and a second portion of the instrument at opposite sides of its longitudinal axis and disposed at predefined angles with respect to said axis.

Within the meaning of this description cables should be understood to embrace all types of long, thin and flexible wires of any suitable thickness or function, such as tubes, glass fibers, electrical wires, coax cables, etc.

The instrument of the invention may be an industrially applicable instrument or a medical device, such as a surgical tool. The tool may be an instrument for minimally invasive surgery, for example intended for laparoscopic surgery, neurosurgery or endo-nasal skull base surgery; a flexible endoscope like a gastroscope or a colonoscope, an instrument for single port surgery or Natoral Orifice Translumenal Endoscopic Surgery (NOTES) or a catheter wherein each said instrument may have flexible or rigid parts. US 2008/0097152 discloses a braided device for use with an endoscope, in the form of a braided flexible tube having cables disposed alongside the tube, which cables are capable upon their retraction of bending the braided tube at a region along its length and holding it at a desired orientation. The braided device has a handle for controlling the steering of the device and locking it in the desired orientation.

Although endoscopes and other instruments for minimally invasive surgery are known already for several decades, the developments of the latest years focus on steerable, flexible or articulated devices as is exemplified by US 2008/0097152.

The application of devices that are steerable implies that the devices are to a certain degree flexible. This flexibility goes at the expense however of the device's rigidity and stiffness. There is however from a surgical point of view a preference for a tool that is easy to steer but at the same time relatively stiff at least at its tip, i.e. at the distal portion of the instrument.

Another notable need is to avail of an instrument that can follow complex trajectories as they occur for instance in the arteries of a patient.

It is an object of the invention to provide an instrument, for instance a surgical tool or a catheter, which can be embodied with a relatively stiff second portion.

It is another object of the invention to provide such an instrument which is uncomplicated to manufacture, and which can therefore be provided at relatively low cost even when, in case the instrument is for instance a minimally invasive surgical tool, its dimensions are at the lower end of what is technically feasible.

It is still another object of the invention to provide a suitable alternative for existing steerable devices with improved steering capabilities and with capability to follow complex (multiple) curves.

These and other objects and advantages of the invention are promoted with an instrument having the features of one or more of the appended claims.

In a first aspect of the invention the instrument has one or more sets of cables, at least one of said sets of cables comprising in combination a first cable running predominantly parallel to the longitudinal axis of the instrument, a second cable running at a first predefined angle with respect to said longitudinal axis, and a third cable running at a second predefined angle with respect to said longitudinal axis and having a sign that is opposite to the sign of the first predefined angle so as to arrange that the second and third cables cross each other. It is possible to apply such a single set of cables, or to apply multiple co-axial sets of cables.

The inventors have found that this construction results in very desirable steering characteristics of the instrument, wherein the instrument can remain flexible between the first portion and second portion, whereas the instrument's second portion, usually the tip, will exhibit high rigidity and stiffness. Also the instruments torsional stiffness is at a relatively high-level in comparison with prior art devices. A preferable aspect of the invention is that within each set of cables the first cable running parallel to the longitudinal axis, the second cable running at the first predefined angle with respect to said longitudinal axis, and the third cable running at the second predefined angle with respect to said longitudinal axis are movable with respect to each other. The said movability may relate to the angle that the respective cables assume with respect to each other, but may also relate to the possibility that the cables in a set of cables are movable in their longitudinal direction. Particularly the last feature provides the possibility that the joint cables can transfer complicated curves from a first portion to a second portion of the instrument, located at opposite sides of the instrument's longitudinal axis. One thing and another promotes the flexibility of the instrument without compromising the rigidity and stiffness of the instrument at its second portion (the tip).

The results of the invention are achievable with an instrument wherein within the at least one of said set of cables, the second cable and the third cable are displaced laterally between the first portion and the second portion over a predefined angle. This can be any angle of a value capable to provide the sought for steering characteristics of the instrument, wherein the instrument can remain both flexible between its first portion and second portion, and wherein the instrument's second portion, i.e. the tip, will exhibit high rigidity and stiffness. Preferably for this purpose the angle is equal to or larger than 30° although occasionally smaller angles may be feasible as well. Best results are achieved when within the at least one set of cables the second cable and the third cable each are displaced laterally between the first portion and the second portion over at least 60°, preferably 90°, more preferably 135°, and most preferably 180°, or any multiple thereof. The application of lateral displacements over multiples of 180° is beneficial when it is intended to include high stiffness positions at intermediate locations between the first portion of the second portion of the instrument, and particularly promotes the possibility to transfer S-shaped curves from a first portion to a second portion of the instrument, that are located at opposite sides of the instrument's longitudinal axis.

Suitably in said predefined area between the first portion and the second portion restriction means are provided to restrict sideways displacement of the cables yet enable their longitudinal movement with respect to said means. It is indeed one of the beneficial aspects of the instrument of the invention that it only requires that the cables are fixed to the first portion and the second portion and only need restriction against sideways displacement but not fixing along their longitudinal direction. This reduces the complexity of the construction and the costs that are associated therewith.

The said restriction means can simply be embodied as guide plates that are extending transversely to the longitudinal axis of the instrument, which plates are provided with slits that receive said cables.

The inventors particularly envisage with an embodiment in which the restriction means are executed as neighbouring cables or tubes that extend adjacent and along at least part of the length of a first cable running predominantly parallel to the longitudinal axis, a second cable running at a first predefined angle with respect to said longitudinal axis, and a third cable running at a second predefined angle with respect to said longitudinal axis. Thus all cables are neighbour to similar adjacent cables and each of said cables in a certain orientation, i.e. longitudinally extending, or obliquely extending with either a left turn or a right turn with reference to the longitudinal axis, then forms part of a set of cables according to the invention. Consistent with the law the invention also applies to any situation that there are more (sets of) cables that are applied concentrically to the first, second and third cable. These additional cables may have other angles with reference to the predominantly parallel extending first cable then the angles of the second and third cable.

The invention will hereinafter be further elucidated with reference to the drawing of some typical examples of an instrument or part of an instrument incorporating the invention .

In the drawing: - figure 1 shows a minimally-invasive surgical device in which for clarity purposes the first or handle portion and the second portion are shown without cover; - figure 2 shows a detailed view of elements that embodied the invention and are applied in the handle portion and second portion of the minimally-invasive surgical device of figure 1; - figure 3 shows a detailed view of the elements of figure 2 completed with several additional sets of cables; and - figure 4 shows another embodiment of an instrument construed according to the invention; - figure 5 a, b, c show a joystick in a transparent view in which the invention is embodied; and - figure 6 shows a surgical instrument in which the handle portion is provided with a joystick as is shown in figure 5 .

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

First making reference to figure 1, an instrument, in particular a minimally-invasive surgical device 1, is shown in which cables 2 extend between a first portion 3 and a second portion 4 of the instrument 1. The cables 2 are clearly provided at opposite sides of the instrument's longitudinal axis 5. Care has been taken that the cables 2 are disposed at predefined angles with respect to said longitudinal axis 5.

The first portion 3 of the instrument 1 shown in figure 1, mostly the handle portion, depicts the basic configuration in which elements of the instrument 1 that do not immediately relate to the invention are for clarity purposes not shown. It shows a basic configuration of a single set of cables 2 in which a first cable 2' runs parallel to the instrument's longitudinal axis 5 between the first portion 3 and the second portion 4 of the instrument 1. Further it is shown that there is a second cable or cables 2'' running at a first predefined angle with respect to said longitudinal axis 5, and a third cable or cables 2''' running at a second predefined angle with respect to said longitudinal axis and having a sign that is opposite to the sign of the first predefined angle of the cable or cables 2'' so as to arrange that the second 2'' and third cables 2''' cross each other. The angle may be selected at any suitable value, for instance 30° or any value higher than 30°.

The first cable 2', the second cable 2'' and the third cable 2''' are movable with respect to each other to arrange that the joint cables 2', 2'', 2''' can transfer complicated curves from a first portion 3 to a second portion 4 of the in strument, located at opposite sides of the instrument's longitudinal axis 5. This means that the angle that the respective cables 2', 2'', 2’’’ assume with respect to each other is adjustable and/or that at least one of the said first, second or third cables 2', 2'', 2''' is movable in its longitudinal direction .

Figure 2 shows for clarity purposes only the second cables 2'' that run at a first predefined angle with respect to the longitudinal axis 5 of the instrument. In this figure it is shown that the second cables 2'' are displaced laterally between the first portion 3 and the second portion 4 over 180°. It can however also be any other value, and even a multiple of 180°. The same applies to the not shown third cables 2' ' ' .

Figure 2 further shows that between the first portion 3 and the second portion 4 restriction means 6 are provided to restrict sideways displacement of the cables 2 yet enable their longitudinal movement with respect to the restriction means 6. The restriction means 6 are embodied as plates 7 that are extending transversely to the longitudinal axis 5 of the instrument 1, which plates 7 are provided with slits 8 that receive said cables 2. See also figure 3 in which a multiple of sets of cables 2 are applied, each set of cables 2 comprising a parallel cable and two crossing cables that extend helically in a opposite direction around the longitudinal axis of the instrument 1. Each of the slits 8 of each plate 7 receives a cable parallel to the longitudinal axis of the instrument, and two crossing cables. The parallel cable and the two crossing cables are mutually displaceable due to the requirement to provide the possibility of longitudinal movement of said cables .

Figure 4 shows an alternative and advantageous embodiment of an instrument according to the invention, wherein the restriction means 6 are embodied as cables 2', 2'', 2''' or tubes that extend adjacent and along at least part of the length of a first cable 2' running parallel to a longitudinal axis, a second cable 2'' running at a first predefined angle with respect to said longitudinal axis, and a third cable 2''' running at a second predefined angle with respect to said longitudinal axis. Thus all cables are neighbour to similar adja cent cables and each of said cables in a certain orientation, i.e. longitudinally extending, or obliquely extending with either a left turn or a right turn with reference to the longitudinal axis, then forms part of a set of cables according to the invention.

Figure 4 further shows that in this embodiment an inner spring 8 and an outer spring 9 may be employed to keep all cables in the assembled condition.

The foregoing figures elucidate the invention with reference to a minimally invasive surgical device but it can be any surgical instrument, endoscope or catheter with a rigid or flexible shaft, although preferably a laparoscopic instrument .

Figure 5A, 5B and 5C show the application of the invention wherein the instrument is a joystick 9. The helically extending cables 2'' and 2''' that cross each other are clearly recognizable, and extend around the longitudinal axis coinciding with the stick 10 of the joystick 9 when it's in its neutral position. Also the cables 2' that run parallel to said longitudinal axis are clearly shown as are the plates 7 that act as guides for the cables 2', 2'', 2' ' ' .

Figure 6 shows an interesting combination in which a surgical tool 12 is provided at its handle 11 with a joystick 9 as shown in figure 5. The specialty of this construction is that the joystick 9 can be moved back and forth in a plane perpendicular to the plane of the drawing while keeping the stick 10 perfectly parallel to the shaft of the instrument.

The parallel orientation of the stick 10 can be maintained independent from the movement of the stick 10 to the left or the right, or backwards or forwards in the longitudinal direction of the instrument shaft. Accordingly the joystick 9 in total assumes the shape of an S-curve and correspondingly also the tip 4 of the instrument assumes a similar S-curve. The instrument and the joystick 9 of the invention therewith exhibit 4 degrees of freedom rather than the usual 2 degrees of freedom. The beauty of this construction is further that a three-dimensional manipulation of the distal tip 4 of the instrument is carried out by manipulating the joystick 9 merely by a single thumb of the user that holds the handle 11.

Although the invention has been discussed in the fore- going with reference to exemplary embodiments of the apparatus of the invention, the invention is not restricted to these particular embodiments which can be varied in many ways without departing from the gist of the invention. The discussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiments are merely intended to explain the wording of the appended claims without intent to limit the claims to these exemplary embodiments. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exemplary embodiments. The description should in particular not be understood in the sense that what is not shown or described would be disclaimed. On the contrary: everything that is not shown or described falls within the scope of protection of the claims, provided that at least the subject-matter covered by the main claim is applied.

Claims (10)

An instrument (1, 9, 12) provided with cables (2) extending in a predetermined area between a first part (3) and a second part (4) of the instrument, which lie on opposite sides of its longitudinal shaft (5) and arranged at predetermined angles with respect to said shaft (5), characterized in that it has one or more sets of cables (2), at least one of said sets of cables (2) in combination a first cable (2 ') extending substantially parallel to the longitudinal axis (5), a second cable (2' ') extending at a first predetermined angle with respect to said longitudinal axis (5), and a third cable (2 '' ') which extends at a second predetermined angle with respect to said longitudinal axis (5) with a sign opposite to the sign of the first predetermined angle to cause the second (2' ') and third (2 '' ') cables intersect. Instrument (1, 9, 12) according to claim 1, characterized in that within each set of cables (2) the first cable (2 ') that runs substantially parallel to the longitudinal axis (5), the second cable {2 '') extending at a first predetermined angle with respect to said longitudinal axis (5), and the third cable (2 '' ') extending at a second predetermined angle with respect to said longitudinal axis (5) be movable relative to each other. Instrument (1, 9, 12) according to claim 2, characterized in that the first cable (2 '), the second cable (2' ') and the third cable (2' '') are movable relative to each other are adjustable so that the angle that the respective cables (2 ', 2' ', 2' '') take with respect to each other and / or that at least one of the cables (2 ', 2' ', 2' '' ) is movable in its longitudinal direction. Instrument (1, 9, 12) as claimed in any of the claims 1-3, characterized in that within the at least one set of cables (2) the second cable {2 '') and the third cable {2 '' ' connecting each laterally offset by a predetermined angle to the first part (3) and the second part (4). Instrument (1, 9, 12) as claimed in any of the claims 1-4, characterized in that within the at least one set of cables (2) the second cable (2 '') and the third cable (2 '' ' ) are each laterally shifted between the first part (3) and the second part (4) by at least 60 °, preferably 90 °, more preferably 135 °, and most preferably 180 °, or any multiple thereof. Instrument (1, 9, 12) as claimed in any of the claims 1-5, characterized in that restriction means (6) are provided in said predetermined area between the first part (3) and the second part (4) for limiting the lateral displacement of the cables (2) but allowing longitudinal movement with respect to the restriction means (6). Instrument (1, 9, 12) according to claim (6), characterized in that the restriction means (6) are designed as plates (7) that extend transversely to the longitudinal axis (5) of the instrument, which plates ( 7) are provided with slots (8) in which said cables (2) are accommodated. Instrument (1, 9, 12) according to claim (6), characterized in that the restriction means (6) are designed as neighboring cables (2 ', 2' ', 2' '') or tubes that run side by side along at least a part of the length of a first cable (2 ') that runs parallel to the longitudinal axis, of a second cable (2' ') that runs at a predetermined angle with respect to said longitudinal axis, and of a third cable (2 '' ') which runs at a second predetermined angle with respect to the longitudinal axis. An instrument (1, 9, 12) according to any one of the preceding claims 1-8, characterized in that the instrument is a surgical instrument, preferably a laparoscopic instrument or a catheter (1). Instrument (1, 9, 12) according to one of claims 1 to 9, characterized in that the instrument is a joystick (9) or is designed as a surgical instrument (12) provided with a joystick (9).