Steerable Instrument for Endoscopic or Invasive Applications

Abstract

1. A steerable instrument for endoscopic and / or invasive, e.g., gastroscopic or colonoscopic, applications in surgery and the like, comprising a cylindrical element having a proximal end, a distal end including a flexible distal portion, and an intermediate portion between the proximal and distal ends, and at least one longitudinal element for transmitting force from the proximal end to the flexible distal portion to control bending of the latter, a tangential spacer disposed adjacent to the longitudinal element, a second cylindrical element coaxial with the cylindrical element, the second cylindrical element having a proximal end, a distal end including a flexible distal portion, and an intermediate portion therebetween, and a radial spacer attached to the second cylindrical element and protruding into an opening in the tangential spacer, wherein movement of the tangential spacer in both the longitudinal and tangential directions of the instrument is limited by the radial spacer.

Description

[Technical field]

[0001] The present invention relates to a steerable instrument for endoscopic and / or invasive applications such as in surgery. The instrument according to the invention is particularly suitable for colonoscopic and / or gastroscopic applications. The steerable instrument according to the invention may be used in both medical and non-medical applications. Examples of the latter include inspection and / or repair of mechanical and / or electronic hardware in hard to reach places. Therefore, terms used in the following description such as endoscopic applications or invasive instrument should be interpreted broadly. [Background technology]

[0002] It is a well-known and ongoing process to transform surgical interventions that require large incisions to expose the target area into minimally invasive surgical interventions, i.e. those in which access to the target area can be established only through natural orifices or small incisions. In performing a minimally invasive surgical intervention, an operator, such as a physician, needs an access device arranged to insert and guide an invasive instrument into the human or animal body through an access port in the body. To reduce the formation of scar tissue and pain for the human or animal patient, the access port is preferably provided by one small incision in the skin and the underlying tissue. In this regard, it is even better if a natural orifice in the body can be used. Furthermore, the access device preferably allows the operator to control one or more degrees of freedom that the invasive instrument has. In this way, the operator can perform the required actions in an ergonomic and precise manner in the target area of ​​the human or animal body, with reduced risk of collision of the instrument used.

[0003] Invasive instruments for surgery and endoscopes within which they are guided towards a target area are well known in the art. Both invasive instruments and endoscopes may include steerable instruments that enhance their navigation and steering capabilities. Such steerable instruments preferably include a proximal end portion including at least one flexible zone, a distal end portion including at least one flexible zone, and a rigid intermediate portion, the steerable instruments further including a steering mechanism adapted to translate a deflection of at least a portion of the proximal end portion into a relative deflection of at least a portion of the distal end portion relative to the rigid intermediate portion.

[0004] Moreover, the steerable instrument preferably comprises a plurality of coaxially arranged cylindrical elements, including an outer element, an inner element and one or more intermediate elements depending on the number of flexibility zones at the proximal and distal ends of the instrument and the desired implementation of the steering members of the steering mechanism, i.e. all steering members can be arranged in one intermediate cylindrical element or the steering members are divided into different sets, each set of steering members being arranged at least partially in a different or the same intermediate member. In most of the prior art instruments, the steering mechanism comprises as steering members conventional steering cables, for example with a diameter of less than 1 mm, which are arranged between the relevant flexibility zones at the proximal and distal ends of the instrument. Alternatively, other steering units, such as a spherical steering unit or a steering unit driven by a robot, can be applied at the proximal end.

[0005] However, steering cables have many well-known drawbacks, so it is preferable to avoid their use and to implement the steering members by one or more sets of longitudinal elements forming an integral part of one or more intermediate cylindrical elements. Each of the intermediate cylindrical elements, including the longitudinal elements, can be manufactured by using a suitable material addition technique, for example injection molding or plating, or by starting with a cylindrical element and then using a suitable material removal technique, for example laser cutting, photochemical etching, conventional chipping techniques such as deep pressing, drilling or milling, or high-pressure water jet cutting systems. Among the above-mentioned material removal techniques, laser cutting is very advantageous, since it allows very precise and clean material removal to be carried out under reasonable economic conditions. Further details regarding the design and manufacture of the above-mentioned steerable instruments and their steering mechanisms are described, for example, in the applicant's PCT Publication No. WO 2009 / 112060 A1, PCT Publication No. WO 2009 / 127236 A1, U.S. Patent Application Publication No. 13 / 160949 and U.S. Patent Application Publication No. 13 / 548,935, all of which are incorporated herein by reference in their entireties.

[0006] Steerable invasive instruments typically include a handle located at the proximal end of the steerable instrument for steering the instrument and / or manipulating a tool located at the distal end of the steerable instrument. Such a tool may be, for example, a camera, a manual manipulator, such as scissors, forceps, or a manipulator that uses an energy source, such as an electrical, ultrasonic, or light energy source.

[0007] Assembling a steerable instrument with an intermediate cylindrical element in a steerable instrument is rather difficult, since the bending stiffness of the intermediate cylindrical element is significantly reduced by the longitudinal elements. The intermediate cylindrical element with the longitudinal steering elements can be deformed in a hardly controlled manner. This easily destroys its geometrical consistency. Manipulating the intermediate cylindrical element during and after the provision of the longitudinal elements therein can be problematic, especially during the assembly of the steerable instrument. This is rather troublesome when performing the assembly and can also cause damage to the intermediate cylindrical element. Such damage generally reduces the performance of the steerable instrument, which is highly undesirable.

[0008] Addressing these problems is WO 2016 / 089202 A1, which discloses a steerable instrument and a method for its manufacture. This method provides an efficient and well-controlled method for manufacturing a steerable instrument. To avoid displacement, deformation and / or cluttering of the longitudinal elements, elements are provided for holding adjacent longitudinal elements and / or in a set relationship relative to each other during assembly of the instrument. These elements may be flexible elements and are permanently attached to the respective longitudinal elements. Alternatively, these elements may be releasably or temporarily attached to the longitudinal elements, for example by elements referred to as break points or break elements. These temporary or releasable attachments may be broken, cut or otherwise removed after assembly of the instrument. An embodiment thereof is reproduced in figures 8a and 8b of the present application.

[0009] The use of the breaking elements described in WO 2016 / 089202 A1 offers many advantages during the assembly of the instrument, but after assembly, they remain in the gap between adjacent longitudinal elements, thereby limiting the relative movement of the two adjacent longitudinal elements. Furthermore, if not properly cut at each breaking point, the relative movement of the longitudinal elements may be further hindered, for example limited to half its initial range. Furthermore, if the instrument operator applies force to the instrument, causing it to bend beyond the range set by the length of the gap due to the relative movement of the adjacent longitudinal elements, the breaking elements may be forced into undesirable positions, for example into the longitudinal slits separating the adjacent longitudinal elements or into the space below or above the longitudinal elements, where it may get stuck or otherwise cause serious damage to the instrument.

[0010] Another problem that may occur during the use of steerable instruments is related to the unintentional pinching of the longitudinal elements between the inner and outer layers. In these steerable instruments, the longitudinal elements need to be flexible at least in the parts of the instrument that allow movement about the longitudinal axis of the instrument at both the proximal and distal ends. These longitudinal elements are often arranged between adjacent outer and adjacent inner cylindrical elements. When bending these flexible zones of the instrument, in each such zone, these longitudinal elements bend together with the bendable parts of the outer and inner cylindrical elements. However, sometimes bending of such zones causes the longitudinal elements to be pinched between the outer and inner cylindrical elements by the bending outer and bending inner cylindrical elements, which makes it difficult to move the longitudinal elements further. This effect may also be caused / enhanced by different longitudinal elements arranged on top of each other in the bendable parts.

[0011] WO 2019 / 009710 A1 describes a steerable instrument having a configuration for preventing pinching of a longitudinal element between an outer and an inner cylindrical element. Several different embodiments are shown for providing a distance between different cylindrical elements to prevent pinching of the longitudinal element between them. In some embodiments, as reproduced in Figures 9a-9c of the present application, a radial spacer is realized by a small lip-shaped portion formed on one cylindrical element, which when it is coaxially aligned with the other cylindrical element, bends radially and contacts the other cylindrical element, thereby providing a distance between them.

[0012] However, the presence of such radial spacers formed by curved lip-shaped portions may limit the extent to which the device can be bent. As shown in Figures 9a-9b, the width of the longitudinal elements varies along their length. The edges of these longitudinal element portions define the gap between adjacent longitudinal elements, thereby limiting the relative movement of adjacent longitudinal elements when the edges of the widened portions contact the radial or tangential spacers.

[0013] Furthermore, in WO 2019 / 009710 A1, if the different cylindrical elements are not aligned precisely enough and / or the point at which the force is applied to bend the lip shaped portion is not precise, the lip shaped portion may not bend as intended, the lip shaped portion may bend unintentionally without contacting the inner cylinder, the desired radial spacing may not be achieved, and / or the lip shaped portion may abut against one or both of the adjacent longitudinal elements, which may cause friction during use of the device.

[0014] Depending on the location within the body to be examined and / or operated on, specially designed instruments may be required, particularly if these locations are relatively far from suitable entry points into the body, and sufficient length of the instrument may be required, and high flexibility may be required in the mid-section of the instrument while still retaining its functionality. Summary of the Invention [Problem to be solved by the invention]

[0015] It is an object of the present invention to provide a steerable instrument for endoscopic and / or invasive applications, in which at least one of the above mentioned problems is overcome or at least mitigated.

[0016] In particular, it is an object of the present invention to provide a steerable instrument having improved bending characteristics, for example a steerable instrument capable of handling higher bending and / or torsional stresses or forces. [Means for solving the problem]

[0017] This is achieved by a steerable instrument as claimed in claim 1.

[0018] In another embodiment, it is an object of the present invention to provide a steerable instrument that can be more easily assembled and / or manufactured, and in particular, the instrument is less prone to defects, errors or imperfections caused by the manufacturing process.

[0019] This is achieved by a cylindrical element as claimed in claim 17.

[0020] Embodiments of the invention are set forth in the dependent claims.

[0021] In a first aspect, there is provided a steerable instrument for endoscopic and / or invasive applications such as in surgery, the instrument comprising: a first cylindrical element including a first proximal end, a first distal end including at least one first flexible distal portion and a first intermediate portion between said first proximal end and said first distal end, and at least one longitudinal element arranged to transmit a force from said first proximal end to said at least one first flexible distal portion, thereby controlling bending of said at least one first flexible distal portion; at least one tangential spacer disposed tangentially adjacent to the at least one longitudinal element in a gap between the at least one longitudinal element and another portion of the first cylindrical element; a second cylindrical element arranged coaxially with the first cylindrical element and including a second proximal end corresponding to and substantially aligned with the first proximal end, the first distal end, and the first intermediate portion of the first cylindrical element, respectively, a second distal end including at least a second flexible distal portion, and a second intermediate portion between the second proximal end and the second distal end; at least one radial spacer attached to the second cylindrical element and projecting into an opening in the tangential spacer, whereby movement of the tangential spacer in both the longitudinal and tangential directions of the steerable instrument is limited by the at least one radial spacer; and optionally at least one further radial spacer attached to the second cylindrical element and projecting into the gap at the longitudinal end of the at least one tangential spacer; Includes.

[0022] The first cylindrical element may also be referred to as an intermediate cylindrical element or layer. The instrument may include two or more such intermediate cylindrical layers depending, for example, on the number of flexible distal zones of the steerable instrument and / or its construction requirements.

[0023] To avoid confusion and to clearly distinguish between the various cylindrical corresponding features, e.g., proximal and distal ends, flexible distal portions, etc., these will be referred to in relation to the cylindrical element on which they are provided. For example, a feature "first proximal end" refers to the proximal end of the first cylindrical element. Alternatively, this feature may also be referred to as the "proximal end of the first cylindrical element."

[0024] At least one longitudinal element is separated from a radially adjacent or nearby portion of the first cylindrical element by at least one tangential spacer. In some embodiments, more than one longitudinal element is provided, e.g., a plurality of longitudinal elements and a plurality of tangential spacers. In such embodiments, adjacent longitudinal elements are separated from each other by at least one tangential spacer disposed therebetween.

[0025] That is, the expression "other portions of the first cylindrical element" as used herein may include any portion of the cylindrical element that extends longitudinally, i.e., that is adjacent to at least one longitudinal element, but does not form a longitudinal element arranged to transmit forces, and any other longitudinal element, including multiple longitudinal elements in some embodiments.

[0026] At least one longitudinal element provides a controlled bending of at least one first flexible distal zone of the instrument. If multiple longitudinal elements are provided, they can be arranged to control the bending of the multiple distal zones. At the proximal end of the steerable instrument, an operator, such as a surgeon, or a computer or robot controls the bending of the one or more flexible distal zones by applying a force to at least one longitudinal element or to at least some of the multiple longitudinal elements. At least one longitudinal element extending between the proximal and distal ends of the instrument transfers this force to the distal end, thereby bending one or more of the flexible distal zones. If two or more flexible distal zones are provided, they can be individually controlled, thereby achieving the bending of the distal end of the instrument as intended by the operator.

[0027] Thus, at the proximal end, the longitudinal element may be connected to a linear actuator controlled by a control unit, such as a computer or a robot. Alternatively, the proximal end of the first cylindrical element may comprise at least one flexible proximal portion, whereby bending of said flexible proximal portion results in a controlled bending of a corresponding flexible distal portion. Such a flexible portion may be implemented by a corresponding hinge in the form of a suitable slit-shaped pattern in the cylindrical element or by a spherical steering unit or a tiltable plate, as will be understood by those skilled in the art.

[0028] The second cylindrical element may also be referred to as an outer cylindrical element or layer. The second cylindrical element may also be an intermediate layer within an associated device, thereby providing another outer layer.

[0029] The different cylindrical elements or layers are coaxially aligned, whereby the corresponding flexible portions are arranged along the cylindrical axis. As will be described below, a third cylindrical element may be provided as an inner cylindrical element or as another intermediate cylindrical element.

[0030] The intermediate section extending between the proximal and distal ends is flexible throughout its extent, allowing it to bend in different directions. This bending is generally not directly controllable by the operator, and occurs, for example, when the instrument contacts a wall or other obstruction therein while being inserted into and / or passing through a space, such as the large or small intestine, depending on, for example, the shape of the space into which the instrument is introduced. The flexibility of the intermediate region must be such that no damage is caused to the inner wall of the passageway through which it passes. A substantially fully bendable and / or flexible instrument is provided, which is suitable for a variety of applications in which the distal end of the steerable instrument must reach a location that is difficult to reach and / or located some distance from the entry point into the body, such as the human body. Examples of such applications include colonoscopic and gastroscopic applications.

[0031] The tangential spacers are arranged to provide and / or maintain distance between at least one longitudinal element and other portions of the first cylindrical element and / or between adjacent longitudinal elements in embodiments including multiple longitudinal elements, and to limit tangential, circumferential and / or transverse movement of the at least one longitudinal element.

[0032] A tangential spacer is provided having at least one opening into which the radial spacer projects, thereby limiting its movement relative to at least one longitudinal element in directions parallel and anti-parallel to the extent of the longitudinal elements as well as in a tangential direction to the first cylindrical element.

[0033] The tangential spacers may be formed by elements attached to at least one longitudinal element prior to assembly of the device via one or more breaking points or breaking elements that break after assembly of the device, for example as described in WO 2016 / 089202 A1.

[0034] In embodiments where multiple longitudinal elements are provided, these are arranged with a gap or distance between longitudinally adjacent longitudinal elements forming gaps. One or more of said tangential spacers can be arranged in each of these gaps. The longitudinal elements preferably have a shape and / or dimensions such that the movement of the longitudinal elements relative to each other and the tangential spacers is not limited by the longitudinal elements themselves or any part thereof.

[0035] By means of at least one radial spacer, the movement of the tangential spacer relative to the second cylindrical element is limited and / or restricted. The tangential spacer can be said to be held in place by the radial spacer. Thus, the distance between adjacent longitudinal elements is maintained by the tangential spacer, while allowing a relative movement of adjacent longitudinal elements along each other, while preventing unintentional displacement of the spacer, for example in the form of the tangential spacer sliding above or below the first cylindrical element.

[0036] The radial spacer projects into and preferably extends through at least one longitudinal element and another part of the adjacent cylindrical element or between adjacent longitudinal elements. It is attached to and / or forms part of the second cylindrical element, for example by being formed by a part of it. Preferably, it is flexible and / or has at least some elasticity or flexibility with respect to the second cylindrical element. The radial spacer may be the radial spacer of the second aspect of the invention.

[0037] Preferably, a plurality of tangential spacers and a plurality of radial spacers are provided between adjacent longitudinal elements.

[0038] The tangential spacers are provided with openings and the radial spacers at least partially protrude into said openings, such that one radial spacer is sufficient to limit the tangential spacer to movement in both the longitudinal and tangential directions of the steerable instrument.

[0039] The first cylindrical element may be a first cylindrical tube, and the at least one longitudinal element and the at least one tangential spacer may both be part of the first cylindrical tube.

[0040] The second cylindrical element may be a second cylindrical tube. The at least one radial spacer and the at least one further radial spacer may be formed by a lip-shaped portion of the second cylindrical tube extending from the second cylindrical tube. The lip-shaped portion may have a lip-shaped portion width and the opening may have an opening width, the lip-shaped portion width being smaller than the opening width or configured such that it secures the tangential spacer when bent into the opening.

[0041] At least one longitudinal element has a longitudinal length and a width in a direction substantially perpendicular to the longitudinal direction of the first intermediate portion, preferably said width being substantially constant throughout said length. This further reduces the risk of the tangential spacer sliding above or below the longitudinal element. If at least one longitudinal element has a uniform width at least over the extent of the intermediate portion of the first cylindrical element and the distance between adjacent longitudinal elements is substantially constant over this portion, the movement of adjacent longitudinal elements relative to each other is not limited by the interaction of the longitudinal element with the tangential or radial spacers.

[0042] The device may further comprise a third cylindrical element arranged coaxially with the first cylindrical element and the second cylindrical element, the first cylindrical element being arranged between the second cylindrical element and the third cylindrical element, and at least one of the following applies: the at least one radial spacer or the at least one further radial spacer is arranged in abutment with the third cylindrical element, engages with the third cylindrical element, and is attached to the third cylindrical element. This arrangement contributes to the mechanical stability of the device.

[0043] The at least one radial spacer provides a distance between the second and third cylindrical elements, which is preferably greater than the radial thickness of the longitudinal elements and the tangential spacers, thereby preventing the at least one longitudinal element from being pinched between the second and third cylindrical elements when the flexibility zone bends.

[0044] The third cylindrical element may advantageously be a third cylindrical tube provided with at least one recess or opening, said at least one radial spacer or said at least one further radial spacer projecting into said at least one recess or opening. With this arrangement, the second and third cylindrical elements are fixed or locked axially, radially and tangentially with respect to each other. The radial spacer or said at least one further radial spacer may comprise a first portion having a first width and a second portion having a second width smaller than said first width, said second portion projecting into said recess or opening. Thereby, the relative fixation of the second and third cylindrical elements may be improved.

[0045] In some embodiments, the third cylindrical tube may be provided with a plurality of recesses or openings, and each of the at least one radial spacer and the at least one further radial spacer protrudes into a respective one of the plurality of recesses or openings. In such embodiments, the at least one radial spacer and the at least one further radial spacer may both include first and second portions.

[0046] A third cylindrical element includes a third proximal end corresponding to and substantially aligned with the first proximal end, the first distal end, and the first intermediate portion, respectively, of the first cylindrical element, a second proximal end including at least a third flexible distal portion, and a third intermediate portion extending between the third proximal end and the third distal end.

[0047] Typically, the third cylindrical element forms the inner cylindrical element, the first cylindrical element forms the middle cylindrical element, and the second cylindrical element forms the outer cylindrical element. This allows for easy manufacture when the radial spacer is provided by a lip-shaped portion of the second cylindrical element, which bends in the radial direction. Alternatively, the second cylindrical element can form the inner cylindrical element and the third cylindrical element can form the outer cylindrical element.

[0048] At least one radial spacer may advantageously be formed by a lip-shaped portion protruding from said second cylindrical element, which may be formed, for example by laser cutting, in the second cylindrical element and which, after assembly and alignment of the cylindrical elements, may be bent radially to form the radial spacer, said bending being performed from the outside in a radially inward direction when the second cylindrical element forms the outer cylindrical element.

[0049] a lip shaped portion may be formed in a second wall of the second cylindrical element and attached thereto via a beam having a beam axis extending substantially perpendicular to the longitudinal direction; the lip shaped portion is defined by a first slit in the second wall, the first slot extending around the periphery of the lip shaped portion except where the lip shaped portion is attached to the beam; the first slit further extends on either side of the beam in a direction substantially parallel to the beam axis on either side of the lip-shaped portion; The beam is defined by a second slit in a second wall on another side of the beam and substantially parallel to the beam axis.

[0050] The steerable instrument may be substantially flexible over its length, in which case the cylindrical element, the second cylindrical element and, if present, the third cylindrical element are provided with one or more flexible portions over their lengths.

[0051] The steerable instrument may include a plurality of tangential and radial spacers and a plurality of longitudinal elements, with at least one tangential spacer and at least one radial spacer being provided between each two adjacent longitudinal elements, i.e., a tangential spacer and its associated radial spacer being provided in each open gap between adjacent longitudinal elements in the middle of the first cylindrical element, thereby providing a steerable instrument with high flexibility.

[0052] Alternatively, the steerable instrument includes a plurality of tangential spacers, a plurality of radial spacers, and a plurality of longitudinal elements; the plurality of longitudinal elements includes a first longitudinal element, a second longitudinal element, and a third longitudinal element; In the first intermediate portion, a first gap is formed between the first longitudinal element and the second longitudinal element; a second gap is formed between the second longitudinal element and the third longitudinal element; At least one tangential spacer and at least one radial spacer are provided within the first gap; An extended tangential spacer is provided within the second gap, the extended tangential spacer extending substantially the entire second gap. Thus, in this embodiment, a combination of tangential and radial spacers is provided in only every other gap, rather than in each gap formed between adjacent longitudinal elements. In the remaining gaps, a second tangential spacer is provided, the second tangential spacer extending substantially the entire gap. This provides a steerable instrument with greater stability than if a combination of tangential and radial spacers were provided in each gap formed between adjacent longitudinal elements.

[0053] According to a second aspect of the present invention there is provided a cylindrical element for use in a steerable instrument, said cylindrical element extending along a cylindrical axis and including a wall, at least one lip shaped portion being formed in said wall, the lip shaped portion is attached to the wall via a beam having a beam axis, the beam axis being disposed on the cylindrical shaped element; the lip shaped portion is defined by a first slot in the wall, the first slot extending around the periphery of the lip shaped portion except where the lip shaped portion is attached to the beam; the first slot further extends on either side of the beam in a direction substantially parallel to the beam axis on either side of the lip-shaped portion; The beam is further defined by a second slot formed in the wall on another side of the beam in a direction substantially parallel to the beam, the slot angle being greater than 0°, preferably greater than 45°, and less than or equal to 90°, more preferably 90°.

[0054] Thereby, the bending direction of the lip-shaped portion is defined with high precision, since the risk of the lip-shaped portion having a direction deviating from the radial direction is reduced. If a force for bending the lip-shaped portion is applied perpendicular to the wall of the cylindrical element, the lip-shaped portion bends around the beam axis. Abutment and / or friction between the radial spacers and adjacent longitudinal elements during use of the instrument is avoided, since the radial spacers have a well-defined position and / or orientation.

[0055] The cylindrical element according to the second aspect may be used as the second cylindrical element of the steerable instrument of the first aspect, the lip shaped portion forming the radial spacer.

[0056] The lip-shaped portion may comprise a first portion having a first width in a direction substantially parallel to the beam axis and a second portion having a second width in a direction substantially parallel to the beam axis, the first portion being arranged between the beam and the second portion, the second width being smaller than the first width. The second portion is advantageously used to engage with and / or be inserted into an opening or recess of another, for example a third, cylindrical element arranged coaxially with the cylindrical element provided with the lip-shaped portion. Thereby, a stable fixation of the cylindrical element may be provided.

[0057] Generally, the lip shaped portion is symmetrical about said beam axis, and the axis is substantially perpendicular to said beam axis.

[0058] The beam axis may extend in a direction substantially perpendicular to said cylindrical axis, which is preferred when the cylindrical element is used to provide a radial spacer in the steerable instrument of the first aspect, where the longitudinal elements extend in a direction parallel to the cylindrical axis of the first cylindrical element.

[0059] Alternatively, the beam axis may extend in a direction oriented at a different angle relative to the cylindrical axis of the cylindrical element. This is advantageous when the cylindrical element is used to provide a radial spacer in a steerable instrument of the first aspect of the embodiment where the longitudinal elements extend in a spiral or helical arrangement relative to the cylindrical axis of the first cylindrical element. In this case, the beam axis is preferably oriented substantially perpendicular to the longitudinal direction at the location of the radial spacer.

[0060] Generally, a plurality of lip shaped portions are provided within the cylindrical element.

[0061] The lip-shaped portion of the second aspect is advantageously used as the lip-shaped portion of the first aspect or as a radial spacer.

[0062] In a third aspect, there is provided a method of manufacturing a cylindrical element for use in a steerable instrument, the cylindrical element extending in the direction of a cylindrical axis, the method comprising: - providing a piece of material for forming a wall of said cylindrical element; - forming a first slot in said material, whereby at least one lip shaped portion is formed in said material and attached thereto via a beam having a beam axis, said first slot extending around said lip shaped portion except where the lip shaped portion is attached to said beam, and further extending on one side of said beam in a direction substantially parallel to said beam axis on either side of said lip shaped portion; - forming a second slot in the wall, the second slot extending in a direction substantially parallel to the beam axis on another side of the beam. and after said manufacturing, said one or more lip shaped portions are located within said wall of said cylindrical element.

[0063] The cylindrical element is preferably the cylindrical element of the second embodiment.

[0064] The beam axis may extend at an angle to the cylinder axis, the angle being greater than 0°, preferably greater than 45° and less than or equal to 90°, more preferably 90°.

[0065] The piece of material may be provided in the form of a cylindrical element or may be wound into a cylindrical element after forming said first and second slots.

[0066] The beam axis may extend in a direction substantially perpendicular to said cylindrical axis. Alternatively, the beam axis may extend in a different direction, the effects and uses of which have been described above with respect to the cylindrical element of the second embodiment.

[0067] In a fourth aspect, there is provided a method of assembling a steerable instrument, the method comprising: - providing a first cylindrical element including a first proximal end, a first distal end including at least a first flexible distal portion, and a first intermediate portion between said first proximal end and said first distal end; - forming at least one longitudinal element extending between said first proximal end and said first distal end and arranged to transmit a force from said first proximal end to said at least one first flexible distal portion and thereby control bending of the at least one first flexible distal portion; - forming at least one tangential spacer attached to said at least one longitudinal element by at least one releasable attachment; - providing a second cylindrical element including a second proximal end, a second distal end including at least a second flexible distal portion, and a second intermediate portion between said second proximal end and said second distal end; - forming at least one lip-shaped portion defined by a first slot in a second wall of the second cylindrical element in the second intermediate region; - providing a third cylindrical element including a third proximal end, a third distal end including at least a third flexible distal portion, and a third intermediate portion between said third proximal end and said third distal end; - sliding the cylindrical elements into each other, whereby the cylindrical elements are arranged substantially coaxially, - applying a force to the at least one lip-shaped portion in a direction substantially perpendicular to the second wall of the second cylindrical element to radially bend the lip-shaped portion. Including, whereby, after said bending, said at least one lip-shaped portion forms at least one radial spacer protruding into the opening of the tangential spacer; and Thereby, after the releasable attachment is released, movement of the tangential spacer along both the longitudinal and tangential directions of the steerable instrument is limited by the at least one radial spacer.

[0068] The steerable instrument of the first aspect may be assembled by a method according to the fourth aspect. Various features of the method may be associated with technical effects and advantages similar to those described above.

[0069] The third cylindrical element may be provided with at least one opening or recess in a third wall of the third cylindrical element, and after said bending, the lip shaped portion engages with said opening or recess.

[0070] The lip shaped portion may be attached to the second wall via a beam having a beam axis, the lip shaped portion including a first portion having a first width in a direction substantially parallel to the beam axis and a second portion having a second width in a direction substantially parallel to the beam axis, the first portion being disposed between the beam and the second portion, the second width being smaller than the first width, and the second portion engaging the opening or recess in the third cylindrical element.

[0071] The method may further comprise the step of releasing said at least one releasable attachment of said at least one tangential spacer after sliding said cylindrical elements into one another.

[0072] The various embodiments described above may be combined with each other, and an embodiment described with respect to one aspect may be applied with respect to one or more of the other aspects as well.

[0073] The cylindrical element mentioned above is preferably manufactured from a cylindrical tube of any suitable material such as stainless steel, cobalt-chromium, shape memory alloys such as Nitinol, plastics, polymers, composites or other cuttable materials. Alternatively, the cylindrical element can be fabricated by a 3D printing process. The thickness of this tube depends on the application. For medical applications, the thickness can be 0.1-2.0 mm, preferably 0.1-1.0 mm, more preferably 0.1-0.5 mm, most preferably 0.2-0.4 mm. The diameter of the cylindrical element depends on the application. For medical applications, the diameter can be 0.5-20 mm, preferably 0.5-10 mm, more preferably 0.5-6 mm. For many applications, the cylindrical element has a circular cross section. However, the term "cylindrical element" is not limited to this interpretation. It can have any other suitable cross section, including an elliptical cross section or a rectangular cross section.

[0074] The slits and openings for making all cylindrical elements, e.g. at least one longitudinal element and at least one tangential spacer, can be made by laser cutting. Smaller slits, made only to separate adjacent elements, can preferably have a width of 5-50 μm, more preferably 15-30 μm.

[0075] In this application, the terms "proximal" and "distal" are defined with respect to an operator, e.g., a robot or a physician, manipulating an instrument or endoscope, e.g., the proximal end is to be interpreted in the surgical field as the part that is closer to the robot or physician, and the distal end is to be interpreted as the part that is further from the robot or physician.

[0076] It is understood that the term "substantially" as used herein refers to manufacturing tolerances that preclude features such as sizes and distances from having exact numerical values. Depending on the manufacturing process used, such tolerances may be less than 10%, preferably less than 5%, and even more preferably less than 1%.

[0077] Other features and advantages of the present invention will become apparent from the description of the invention by non-limiting and non-exclusive embodiments. These embodiments shall not be interpreted as limiting the scope of protection. Those skilled in the art will appreciate that other alternatives and equivalent embodiments of the invention can be conceived and practiced without departing from the scope of the invention. The embodiments of the present invention will be described with reference to the accompanying drawings below, in which like reference symbols refer to the same or corresponding parts. [Brief description of the drawings]

[0078] [Figure 1] FIG. 1 shows a schematic perspective view of an invasive instrument assembly having two steerable instruments according to the prior art. [Diagram 2] FIG. 1 illustrates a side view of a non-limiting embodiment of a steerable invasive instrument according to the prior art. [Figure 3a] 1 shows a schematic diagram of a colonoscopy instrument in use. [Figure 3b] 1 shows a schematic diagram of a gastroscopic instrument in use. [Figure 4a] 1 provides a detailed perspective view of one embodiment of an elongated tubular body of a steerable instrument. [Figure 4b] 4b provides a more detailed view of the distal end of the elongated tubular body shown in FIG. 4a. [Figure 4c] FIG. 4b shows a longitudinal cross-sectional view of the elongated tubular body of the steerable instrument shown in FIG. 4a. [Figure 4d] FIG. 4b shows a longitudinal cross-sectional view of the elongated tubular body of the steerable instrument shown in FIG. 4a with one proximal and one distal flexibility zone bent, illustrating the operation of the steering mechanism. [Figure 4e]FIG. 4c shows a longitudinal cross-sectional view of the elongate tubular body of the steerable instrument shown in FIG. 4e, with additionally the second proximal and second distal flexibility zones bent, further illustrating the operation of the steering mechanism. [Figure 4f] 1 shows a longitudinal cross-sectional view of an embodiment of a steerable instrument having one proximal and one distal flexibility zone. [Figure 4g] FIG. 4f shows an exploded perspective view of three cylindrical elements of the steerable instrument shown in FIG. [Figure 4h] 4g shows a top view of an embodiment of an intermediate cylindrical element of the steerable instrument shown in Fig. 4g in an open state, which may be formed by rolling the open state into a cylindrical state and attaching adjacent sides of the rolled up configuration by any known attachment means, such as welding techniques. [Figure 4i] 4b shows a perspective view of a portion of the elongated tubular body shown in FIG. 4a illustrating an embodiment of a longitudinal steering element obtained after the outer cylindrical element has been partially removed and a longitudinal slit has been provided in the wall of the intermediate cylindrical element interconnecting a first proximal flexibility zone and a first distal flexibility zone of the elongated tubular body. [Diagram 5] 1 shows a schematic cross-sectional view of another embodiment of a steerable invasive instrument in which a linear actuator is provided at the proximal end for controlling bending of the distal end of the steerable instrument. [Figure 6] FIG. 4g shows an exploded perspective view of three cylindrical elements of a steerable instrument similar to the embodiment of FIG. 4g, but where the diameter of the cylindrical elements varies. [Figure 7] 4c shows schematic cross-sectional views of steerable instruments comparable to the embodiment shown in FIG. 4d, but with cylindrical elements having different diameters. [Figure 8a-8b] A detail of a prior art intermediate cylindrical element with a breakaway element is shown in perspective view (8a) and side view (8b) respectively. [Figure 9a-9c] FIG. 2 shows a schematic diagram of an embodiment of a steerable instrument known from the prior art, in which an inwardly bending lip-shaped portion is used. [Figure 10]13 shows a portion of an intermediate section of an intermediate cylindrical element for a steerable instrument according to an embodiment of the present invention. [Figure 11a-11b] 11 shows the intermediate cylindrical element of FIG. 10 coaxially aligned with the outer cylindrical element, according to an embodiment. [Figure 12] 1 shows a portion of an inner cylindrical element according to an embodiment. [Figure 13a-13b] 11a, 11b are shown coaxially aligned with the cylindrical element of FIG. [Figure 14] 1 shows an expanded view of a tangential spacer according to an embodiment of the present invention. [Figure 15] 1 shows a lip-shaped portion for use as a radial spacer, as known from the prior art; [Figure 16-17] 1 illustrates an embodiment of a lip-shaped portion for use as a radial spacer, according to an embodiment of the present invention. [Fig. 18a-18c] 1 shows a portion of an outer cylindrical element provided with a lip-shaped portion according to an embodiment of the present invention. [Figure 19] 13 shows a portion of an outer cylindrical element provided with a lip-shaped portion that forms a radial spacer that engages with an inner cylindrical element, according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0079] Figure 1 illustrates a non-limiting embodiment of an invasive instrument assembly 1 having an introducer with two steerable invasive instruments 10. Figure 2 illustrates a non-limiting embodiment of such a steerable invasive instrument 10. Details of the steerable invasive instruments 10 are described with respect to Figures 4a-4i.

[0080] FIG. 2 shows a side view of a steerable invasive instrument 10. The steerable instrument 10 comprises an elongated tubular body 18 having a proximal end 11 with two working flexible zones 14, 15 (also called flexible proximal zones), a distal end 13 with two flexible distal zones 16, 17, and a rigid intermediate section 12. These flexible proximal zones 14, 15 are attached and / or connected to the flexible distal end by suitable longitudinal elements (not shown in FIG. 2). Bending one such flexible proximal zone 14, 15 also bends the respective corresponding flexible distal zone, which will be described in more detail below. The rigid intermediate section may also have one or more bendable zones. However, these bendable zones are only flexible and their bending is not controlled by other bendable zones. If necessary, two or more steerable flexible distal zones can be provided. At the distal end 13, a tool such as a forceps 2 is placed. A handle 3 is disposed at the proximal end 11 for opening and closing the jaws of the forceps 2, for example, via suitable cables (not shown) disposed within the instrument. Cable arrangements for doing so are well known in the art.

[0081] In the embodiment shown in FIG. 2, intermediate section 12 is rigid and ultimately has one or more bendable zones, which works well for many applications, but in other applications such as colonoscopy and gastroscopy, it is desirable for intermediate section 12 to be flexible and / or bendable along substantially its entire length.

[0082] FIG. 3a shows a schematic diagram of a colonoscope 42 in use. The colonoscope 42 is inserted into the large intestine 30 of a human body. Typically, the large intestine 30 has several roughly right-angled portions 32, 34, 36, 38. If a surgeon needs to operate on the region of the large intestine upstream of the right-angled portion 32, the colonoscope 42 must be inserted into the large intestine 30 along a distance of up to 1.5 meters. Furthermore, the colonoscope 42 needs to be flexible so that it can be easily guided from the anus through all the right-angled portions 32-38 of the large intestine 30 without risking to damage the inner wall of the large intestine 30.

[0083] During operation, several invasive instruments are typically inserted through the colonoscope 42, providing at its distal end 44 one or more tools for several functions. In the case of a colonoscope, such tools typically include a camera lens and lighting elements. The distal end is typically deflectable in all angular directions from the longitudinal axis to assist the surgeon in maneuvering the camera's field of view to a desired position and viewing the inside of the colon 30. This is also true for the instruments inserted with the tool 2. This can be implemented by providing such an instrument with one or more flexibility zones similar to the flexibility zones 16, 17 of the instrument shown in FIG. 2. These distal flexibility zones are controlled by suitable steering cables, also referred to herein as longitudinal elements, housed within the instrument and / or attached at the proximal end of the instrument to a suitable steering mechanism. Such a steering mechanism can be, for example, the steering mechanism shown in FIG. 5 and / or can be controlled by a robot.

[0084] 3b shows a schematic diagram of a gastroscope 56 in use. The gastroscope 56 is inserted into the stomach 50 of a human body via the mouth, oral cavity / throat 54 and esophagus 52. Especially if the surgeon needs to operate on the lower part of the stomach 50, the gastroscope 56 has to be guided through several curved / angled sections. Therefore, the gastroscope 56 needs to be flexible so that there is little risk of damaging the inner walls of the mouth / throat 54, esophagus 52 and stomach 50.

[0085] In operation, several invasive instruments are typically inserted through the gastroscope 56, providing at its distal end 60 one or more tools for several functions. In the case of a gastroscope, such tools typically include a camera lens and a lighting element. To assist the surgeon in manipulating the camera's field of view to a desired location and orientation within the stomach 50, the distal end 60 of the instrument is typically deflectable in all angular directions from the longitudinal axis. This is also true for the instruments inserted with the tool 2. This can be implemented by providing such instruments with one or more flexibility zones similar to the flexibility zones 16, 17 of the instruments shown in FIG. 2. These distal flexibility zones are controlled by suitable steering cables, also referred to herein as longitudinal elements, housed within the instruments and connected to suitable steering mechanisms of these instruments.

[0086] The steerable instruments according to the invention can be used in such colonoscopes and gastroscopes. Thus, the general requirements of the presented instruments are that they exhibit high rotational stiffness along their entire length, high longitudinal stiffness, flexibility and deflectability in their flexible distal zone, even in long instruments, e.g. more than 1 m, with a relatively small caliber to fit into the working channel in or attached to the colonoscope and gastroscope. Such instruments should also be designed so that they can be manufactured very easily. According to the invention, this can be achieved by an instrument having a tubular body with at least one tube element made of metal and provided with a suitable slotted structure to provide the instrument with sufficient flexibility over its entire length.

[0087] In Figures 4a-4e, an embodiment of a steerable instrument is shown that includes two flexible distal zones. However, it should be understood that other numbers of flexible distal zones are possible. Furthermore, in the embodiment shown in Figures 4a-4i, the flexible distal zones are controlled or actuated via the flexible proximal zone. However, it should be understood that alternatively, the flexible distal zones may be controlled by other means, such as a robot, such as a mechanism as shown in Figure 5. The discussion of the intermediate and distal portions 12, 13 of the instrument applies equally to other methods of controlling one or more flexible distal zones.

[0088] 4a provides a detailed perspective view of a distal portion of the elongated tubular body 18 of the steerable instrument 10, showing that the elongated tubular body 18 comprises multiple coaxially arranged layers or cylindrical elements, including an outer cylindrical element 104 that terminates after the first flexible distal zone 16 at a distal end portion 13. The distal end portion 13 of the outer cylindrical element 104 is disposed within the outer cylindrical element 104 and is securely attached to the adjacent cylindrical element 103, for example by spot welding at weld spots 100. However, any other suitable attachment method may be used, including any mechanical snap-fit ​​connection or gluing with a suitable glue.

[0089] FIG. 4b provides a more detailed view of the distal end 13, showing that it comprises three coaxially arranged layers or cylindrical elements: an inner cylindrical element 101, a first intermediate cylindrical element 102 and a second intermediate cylindrical element 103. The distal ends of the inner cylindrical element 101, the first intermediate cylindrical element 102 and the second intermediate cylindrical element 103 are preferably securely attached to each other, all three. This may be done by spot welding at welding spots 100. However, any other suitable attachment method may be used, including any mechanical snap-fit ​​connection or gluing with a suitable glue. The attachment points may be at the edges of the inner cylindrical element 101, the first intermediate cylindrical element 102 and the second intermediate cylindrical element 103, as shown in the figure. However, these attachment points may also be located at some distance from these edges, i.e. preferably between the edges and the location of the flexibility zone 17.

[0090] It will be clear to those skilled in the art that the elongated tubular body 18 shown in Fig. 4a includes a total of four cylindrical elements. The elongated tubular body 18 according to the embodiment shown in Fig. 4a includes two intermediate cylindrical elements 102 and 103 in which the steering members or longitudinal elements of the steering mechanism are disposed. The steering mechanism of the exemplary embodiment of the elongated tubular body 18 shown in Fig. 4a includes two flexibility zones 14, 15 at the proximal end 11 of the elongated tubular body 18, two flexibility zones 16, 17 at the distal end 13 of the elongated tubular body 18, and steering members disposed between the associated flexibility zones at the proximal end 11 and the distal end 13. An exemplary actual arrangement of the steering members is shown in Fig. 4c, which provides a schematic longitudinal cross-sectional view of the exemplary embodiment of the elongated tubular body 18 shown in Fig. 4a.

[0091] FIG. 4 c shows a cross section of the four layers or cylindrical elements mentioned above, namely the inner cylindrical element 101 , the first intermediate cylindrical element 102 , the second intermediate cylindrical element 103 and the outer cylindrical element 104 .

[0092] The inner cylindrical element 101, viewed along its length from the distal end to the proximal end of the instrument, includes a rigid ring 111 disposed at the distal end 13 of the steerable instrument 10, a first flexible portion 112, a first intermediate rigid portion 113, a second flexible portion 114, a second intermediate rigid portion 115, a third flexible portion 116, a third intermediate rigid portion 117, a fourth flexible portion 118 and a rigid end portion 119 disposed at the proximal end portion 11 of the steerable instrument 10.

[0093] First intermediate cylindrical element 102, viewed along its length from the distal to the proximal end of the instrument, includes a rigid ring 121, a first flexible portion 122, a first intermediate rigid portion 123, a second flexible portion 124, a second intermediate rigid portion 125, a third flexible portion 126, a third intermediate rigid portion 127, a fourth flexible portion 128, and a rigid end portion 129. Portions 122, 123, 124, 125, 126, 127, and 128 together form a longitudinal element 120, which may move longitudinally like a wire. The longitudinal dimensions of the rigid ring 121, the first flexible portion 122, the first intermediate rigid portion 123, the second flexible portion 124, the second intermediate rigid portion 125, the third flexible portion 126, the third intermediate rigid portion 127, the fourth flexible portion 128 and the rigid end portion 129 of the first intermediate element 102 are aligned with, and preferably not only approximately equal to, but also coincident with, the longitudinal dimensions of the rigid ring 111, the first flexible portion 112, the first intermediate rigid portion 113, the second flexible portion 114, the second intermediate rigid portion 115, the third flexible portion 116, the third intermediate rigid portion 117, the fourth flexible portion 118 and the rigid end portion 119 of the inner cylindrical element 101, respectively. In this description, "approximately equal" means that each identical dimension is equal to a difference of less than 10%, preferably less than 5%.

[0094] Similarly, the first intermediate cylindrical element 102 includes one or more other longitudinal elements, one of which is designated by reference numeral 120a.

[0095] The second intermediate cylindrical element 103, viewed along its length from the distal end to the proximal end of the instrument, includes a first rigid ring 131, a first flexible portion 132, a second rigid ring 133, a second flexible portion 134, a first intermediate rigid portion 135, a first intermediate flexible portion 136, a second intermediate rigid portion 137, a second intermediate flexible portion 138, and a rigid end portion 139. Portions 133, 134, 135, and 136 together form a longitudinal element 130, which may move longitudinally like a wire. The longitudinal dimensions of the first rigid ring 131, the first flexible portion 132 as well as the second rigid ring 133 and the second flexible portion 134, the first intermediate rigid portion 135, the first intermediate flexible portion 136, the second intermediate rigid portion 137, the second intermediate flexible portion 138 and the rigid end portion 139 of the second intermediate cylinder 103 are aligned with, and preferably not only approximately equal to, the longitudinal dimensions of the rigid ring 111, the first flexible portion 112, the first intermediate rigid portion 113, the second flexible portion 114, the second intermediate rigid portion 115, the third flexible portion 116, the third intermediate rigid portion 117, the fourth flexible portion 118 and the rigid end portion 119 of the first intermediate element 102, respectively.

[0096] Similarly, the second intermediate cylindrical element 103 includes one or more other longitudinal elements, one of which is designated with reference numeral 130a.

[0097] The outer cylindrical element 104, viewed along its length from the distal end to the proximal end of the instrument, includes a first rigid ring 141, a first flexible portion 142, a first intermediate rigid portion 143, a second flexible portion 144, and a second rigid ring 145. The longitudinal dimensions of the first flexible portion 142, the first intermediate rigid portion 143, and the second flexible portion 144 of the outer cylindrical element 104 are aligned with, and preferably approximately equal to, and coincident with, the longitudinal dimensions of the second flexible portion 134, the first intermediate rigid portion 135, and the first intermediate flexible portion 136, respectively, of the second intermediate element 103. The rigid ring 141 has approximately the same length as the rigid ring 133 and is securely attached thereto, for example by spot welding or gluing. Preferably, the rigid ring 145 overlaps the second intermediate rigid portion 137 only as far as necessary to provide a sufficiently secure attachment, e.g., by spot welding or gluing, between the rigid ring 145 and the second intermediate rigid portion 137, respectively. The rigid rings 111, 121 and 131 are attached to one another, e.g., by spot welding or gluing. This can be at their edges and also at points away from these edges.

[0098] In an embodiment, the same may be true for the rigid end portions 119, 129 and 139, which may also be attached to each other in a similar manner. However, the configuration may be such that the diameter of the cylindrical element at the proximal portion is larger or smaller with respect to the diameter at the distal portion. In such an embodiment, the configuration of the proximal portion differs from that shown in FIG. 4c. By increasing or decreasing the diameter, amplification or attenuation is achieved, i.e. the bending angle of the flexible zone at the distal portion is larger or smaller than the bending angle of the corresponding flexible portion at the proximal portion.

[0099] The inner and outer diameters of the cylindrical elements 101, 102, 103 and 104 are selected such that, at the same location along the elongated tubular body 18, the outer diameter of the inner cylindrical element 101 is slightly smaller than the inner diameter of the first intermediate cylindrical element 102, the outer diameter of the first intermediate cylindrical element 102 is slightly smaller than the inner diameter of the second intermediate cylindrical element 103, and the outer diameter of the second intermediate cylindrical element 103 is slightly smaller than the inner diameter of the outer cylindrical element 104, thereby allowing adjacent cylindrical elements to slide relative to each other. The dimensions should be determined so that a slip fit is provided between adjacent elements. The clearance between adjacent elements can typically be on the order of 0.02-0.1 mm, depending on the specific application and materials used. The clearance is preferably smaller than the wall thickness of the longitudinal elements to prevent their overlapping configuration. It is generally sufficient to limit the clearance to about 30%-40% of the wall thickness of the longitudinal elements.

[0100] As can be seen in Fig. 4c, the flexible zone 14 of the proximal end 11 is attached to the flexible zone 16 of the distal end 13 by the portions 134, 135, 136 of the second intermediate cylindrical element 103, which form a first set of longitudinal steering members of the steering mechanism of the steerable instrument 10. Furthermore, the flexible zone 15 of the proximal end 11 is attached to the flexible zone 17 of the distal end 13 by the portions 122, 123, 124, 125, 126, 127 and 128 of the first intermediate cylindrical element 102, which form a second set of longitudinal steering members of the steering mechanism. By using the above described configuration, the steerable instrument 10 can be used for double bending. The operating principle of this configuration is explained with respect to the example shown in Figs. 4d and 4e.

[0101] For convenience, as shown in Figures 4c, 4d and 4e, the various portions of cylindrical elements 101, 102, 103 and 104 are grouped into zones 151-160, which are defined as follows: Zone 151 includes rigid rings 111, 121 and 131; Zone 152 includes portions 112, 122 and 132; Zone 153 includes rigid rings 133 and 141 and portions 113 and 123; Zone 154 includes portions 114, 124, 134 and 142; Zone 155 includes portions 115, 125, 135 and 143; Zone 156 includes portions 116, 126, 136 and 144; Zone 157 includes rigid ring 145 and the portions of portions 117, 127 and 137 which coincide therewith. Zone 158 includes those portions of sections 117, 127, and 137 that are outside of zone 157. Zone 159 includes sections 118, 128, and 138. Finally, zone 160 includes rigid end portions 119, 129, and 139.

[0102] Although the portions 115, 125, 135 and 143 constituting zone 155 have been described herein as being rigid, alternatively, these portions may be flexible or bendable, for example if the instrument is an instrument used in colonoscopy or gastroscopy as described above. However, unlike the flexible distal portion, the flexing or bending of the intermediate portion is not controlled by the operator of the instrument. Embodiments of such flexible intermediate portions are provided by the present invention and are described in more detail below, for example with respect to Figures 10-19.

[0103] To deflect at least a portion of the distal end 13 of the steerable instrument 10, a bending force can be applied to zone 158 in either radial direction. According to the example shown in Figures 4d and 4e, zone 158 is bent downwards with respect to zone 155. As a result, zone 156 is bent downwards. Due to the first set of steering members including portions 134, 135 and 136 of the second intermediate cylindrical element 103 arranged between the second intermediate rigid portion 137 and the second rigid ring 133, the downward bending of zone 156 is transferred to an upward bending of zone 154 with respect to zone 155 by a longitudinal displacement of the first set of steering members. This is shown in both Figures 4d and 4e.

[0104] The exemplary downward bending of zone 156 causes zone 154 at the distal end of the instrument to bend upward, as shown in FIG. 4d. Bending of zone 152 as a result of bending of zone 156 is prevented by zone 153, which is disposed between zones 152 and 154. Any radial bending force then applied to zone 160 causes zone 159 to bend upward as well. As shown in FIG. 4e, zone 160 is bent upward with respect to its position shown in FIG. 4f. As a result, zone 159 is bent upward. Due to the second set of steering members, including portions 122, 123, 124, 125, 126, 127 and 128 of the first intermediate cylindrical element 102 disposed between the rigid ring 121 and the rigid end portion 129, the upward bending of zone 159 is transferred to a downward bending of zone 152 with respect to its position shown in FIG. 4d by the longitudinal displacement of the second set of steering members.

[0105] FIG. 4e further illustrates that the initial bending of the instrument in zone 154 as shown in FIG. 4d is preserved because it is determined solely by the bending of zone 156, whereas the bending of zone 152 is determined solely by the bending of zone 159, as previously described. Because zones 152 and 154 are capable of bending independently of one another, the distal end portion 13 of the steerable instrument 10 can be given an independent position and longitudinal orientation relative to one another. In particular, the distal end portion 13 can assume an advantageous S-shape. Those skilled in the art will appreciate that the ability to bend zones 152 and 154 independently of one another greatly enhances the maneuverability of the distal end portion 13, and thus the entire steerable instrument 10.

[0106] Obviously, the length of the flexible portions shown in Figures 4c-4e can be varied to accommodate specific requirements regarding the bending radius and overall length of the distal end 13 and proximal end 11 of the steerable device 10, or to accommodate the amplification or damping ratio between bending of at least a portion of the proximal end 11 and at least a portion of the distal end 13.

[0107] The steering member comprises one or more sets of longitudinal elements forming an integral part of one or more of the intermediate cylindrical elements 102, 103. Preferably, the longitudinal elements comprise the remaining portions of the walls of the intermediate cylindrical elements 102, 103 after the walls of the intermediate cylindrical elements 102, 103 are provided with longitudinal slits that define the remaining longitudinal steering elements.

[0108] Further details regarding the manufacture of this longitudinal steering element are provided with reference to Figures 4f-4h, which relate to an exemplary embodiment of a steerable instrument that includes only one flexibility zone at both its proximal and distal ends 11, 13.

[0109] 4f shows a longitudinal cross-sectional view of a steerable instrument 2201 including three coaxially arranged cylindrical elements: an inner cylindrical element 2202, a middle cylindrical element 2203 and an outer cylindrical element 2204. Suitable materials used to manufacture the cylindrical elements 2202, 2203 and 2204 include stainless steel, cobalt-chromium, shape memory alloys such as Nitinol®, plastics, polymers, composites or other cuttable materials. Alternatively, the cylindrical elements may be fabricated by a 3D printing process.

[0110] The inner cylindrical element 2202 includes a first rigid end portion 2221 disposed at the distal end 13 of the instrument 2201, a first flexible portion 2222, an intermediate rigid portion 2223, a second flexible portion 2224 and a second rigid end portion 2225 disposed at the proximal end 11 of the instrument 2201.

[0111] The outer cylindrical element 2204 also includes a first rigid end 2241, a first flexible portion 2242, an intermediate rigid portion 2243, a second flexible portion 2244, and a second rigid end 2245. The lengths of the various portions of the cylindrical elements 2202 and 2204 are substantially the same, so that when the inner cylindrical element 2202 is inserted into the outer cylindrical element 2204, the various portions are positioned opposite one another.

[0112] The intermediate cylindrical element 2203 also has a first rigid end 2331 and a second rigid end 2335 which, in assembled condition, are disposed between corresponding rigid portions 2221, 2241 and 2225, 2245, respectively, of the other two cylindrical elements 2202, 2204. The intermediate portion 2333 of the intermediate cylindrical element 2203 includes three or more separate longitudinal elements, which can have different forms and shapes as described below. When the three cylindrical elements 2202, 2203 and 2204 are assembled, with element 2202 inserted into element 2203 and the two combined elements 2202, 2203 inserted into element 2204, the first rigid end 2221 of the inner cylindrical element 2202, the first rigid end 2331 of the middle cylindrical element 2203 and the first rigid end 2241 of the outer cylindrical element 2204 are attached to each other at the distal end of the instrument. In the embodiment shown in Figures 4f and 4g, the second rigid end 2225 of the inner cylindrical element 2202, the second rigid end 2335 of the middle cylindrical element 2203 and the second rigid end 2245 of the outer cylindrical element 2204 are also attached to each other at the proximal end of the instrument, whereby the three cylindrical elements 2202, 2203, 2204 form one integral unit.

[0113] Although intermediate sections 2223, 2333 and 2243 have been described herein as being rigid, alternatively, these sections may be flexible or bendable, for example if the instrument is one used in colonoscopy or gastroscopy as described above. However, unlike the flexible distal sections, the flexing or bending of the intermediate sections is not controlled by the operator of the instrument. Embodiments of such flexible intermediate sections are provided by the present invention and are described in more detail below, for example with respect to Figures 10-19.

[0114] In the embodiment shown in Fig. 4g, the intermediate portion 2333 of the intermediate cylindrical element 2203 includes a plurality of longitudinal elements 2338 having a uniform cross section, such that the intermediate portion 2333 has an overall shape and configuration as shown in Fig. 4h in the open state of the intermediate cylindrical element 2203. From Fig. 4h it is also clear that the intermediate portion 2333 is defined by a plurality of parallel longitudinal elements 2338 evenly spaced along the circumference of the intermediate cylindrical portion 2203. Advantageously, the number of longitudinal elements 2338 is at least three, such that the instrument 2201 is fully controllable in either direction, although a higher number is possible. Preferably, the number of longitudinal elements 2338 is six or eight.

[0115] The manufacture of such an intermediate section is most conveniently performed by injection molding or plating methods or by starting with a cylindrical tube having the desired inner and outer diameters and removing the necessary portions of the cylindrical tube's wall to ultimately result in the desired shape of the intermediate cylindrical element 2203. However, alternatively, any 3D printing method can be used.

[0116] The removal of material can be done in various ways, such as laser cutting, photochemical etching, conventional chipping techniques such as deep pressing, drilling or milling, high pressure water jet cutting systems or any other suitable material removal process available. Preferably, laser cutting is used, since it allows very precise and clean removal of material in reasonable economic terms. The above process is an advantageous method, since the member 2203 can be made in one process so to speak, and does not require additional steps to attach the different parts of the intermediate cylindrical element, as is necessary for conventional instruments, where conventional steering cables must be connected to the ends in one way or another. The same type of technology can be used to manufacture the inner and outer cylindrical elements 2202 and 2204 with their respective flexible parts 2222, 2224, 2242 and 2244.

[0117] FIG. 4i shows an exemplary embodiment of the longitudinal (steering) element 4 obtained after providing the wall of the second intermediate cylindrical element 103 with a longitudinal slit 5 interconnecting the flexible proximal zone 14 and the flexible distal zone 16 as described above. That is, the longitudinal steering element 4 is at least partially helical around the longitudinal axis of the instrument, whereby an end portion of each steering element 4 at the proximal portion of the instrument is arranged in a different angular orientation around the longitudinal axis than an end portion of the same longitudinal steering element 4 at the distal portion of the instrument. If the longitudinal steering element 4 is arranged in a linear orientation, bending of the instrument at the proximal portion in a particular plane will cause the instrument at the distal portion to bend in the same plane, but in the opposite direction by 180 degrees. This helical configuration of the longitudinal steering element 4 has the effect that bending of the instrument at the proximal portion in a particular plane can result in bending of the instrument at the distal portion in the same direction in another plane or in the same plane. A preferred helical configuration is one in which each steering element 4 at the proximal portion of the instrument is positioned at an angular position offset by 180 degrees around the longitudinal axis relative to an end portion of the same longitudinal steering element 4 at the distal portion of the instrument. However, other angular positions, such as offset by 90 degrees, are within the scope of the present application. The slits are sized such that movement of the longitudinal elements is guided by adjacent longitudinal elements when provided at a predetermined position within the steerable instrument.

[0118] The flexible portions 112, 132, 114, 142, 116, 144, 118 and 138 shown in Figure 4c and the flexible portions 2222, 2224, 2242 and 2244 shown in Figures 4f and 4g are obtained by the method described on page 5, lines 15-26 of European Patent Application No. 08004373.0, filed on October 3, 2008, although any other suitable process can be used for the manufacture of the flexible portions.

[0119] Such a flexible part may have the structure shown in Figures 4a and 4b. That is, flexibility may be obtained by a plurality of slits 14a, 15a, 16a, 17a. For example, two circumferential slits may be provided along the same circumferential line of the cylindrical element, each slit being located at a specific distance from each other. A plurality of identical sets of circumferential slits 14a, 15a, 16a, 17a may be provided at a plurality of distances in the longitudinal direction of the instrument, with successive sets being located at angularly rotated positions, for example 90 degrees each time. In such an arrangement, all parts of the cylindrical element are still attached to each other.

[0120] Furthermore, the above-mentioned manufacturing method can be used if the portions 122, 123, 124, 125, 126, 127 and 128 of the first intermediate cylindrical element 102 and the portions 134, 135 and 136 of the second intermediate cylindrical element 103, which respectively form the first and second sets of longitudinal steering members as shown in Fig. 4c, are implemented as a longitudinal steering element 4 as shown in Fig. 4g. The same applies to the longitudinal element 2338 of Figs. 4g and 4i. Furthermore, any of the embodiments described in EP 2 762 058 A can be used according to the present invention.

[0121] Alternatively, the longitudinal elements 4, 2338 may be obtained by any other technique known in the art, for example as described in EP 1 708 609 A. The only constraint on the configuration of the longitudinal elements used in these sections is that the full flexibility of the instrument must be preserved in those locations where the flexible sections coincide.

[0122] The different coaxially arranged layers or cylindrical elements 101, 102, 103, 104, 2202, 2203 and 2204 described above with respect to the exemplary embodiment of the steerable instrument shown in Figures 4c, 4d and 4d, respectively, can be manufactured by any known method suitable for producing a multi-layer system, which is understood to be a steerable instrument comprising at least two separate sets of longitudinal elements 4, 2338 for transmitting the movement of the proximal end to the distal end. An assembly of different cylindrical elements can be realized as well. A method for manufacturing different cylindrical elements is described in the aforementioned European Patent No. 2762058A, which is incorporated herein in its entirety by reference.

[0123] In the embodiment described above, the proximal and distal portions are similarly constructed, however, as noted above and as will become apparent below, this is not always necessary.

[0124] In the embodiment shown in FIG. 5, the distal end portion 13 is similar to the distal end portion 13 of the embodiment shown in FIGS. 4d and 4e, for example, but the proximal end portion 11 is modified. Around the proximal end portion 11′, a cylindrical housing 80 is provided, which is attached to the outer layer of the instrument or to an outer cylindrical element 104. Furthermore, the outer layer of the instrument at the proximal end portion is provided with a cylindrical member 83, and between the zone 155 and the cylindrical member 83, there are a number of slits 67. On the inner wall of the cylindrical housing 80, two sets of linear actuators 81 and 82, respectively, are attached. Linear actuators are devices that can cause a translational movement of an element, for example a longitudinal element, in this type of steerable instrument. Such linear actuators are generally known in the art and will not be described in more detail here, but they can be controlled by electronic devices, such as a computer.

[0125] The longitudinal elements of the second intermediate layer 103 pass through the slits 67 and are connected to a set of linear actuators 81. The longitudinal elements of the first intermediate layer 102 pass through the cylindrical member 83 and are connected to a second set of linear actuators 82. By appropriate actuation of the linear actuators 81 and 82, the flexible distal zones 152 and 154 can be modified to the same effect as in the embodiment according to figures 4d and 4e. The actuation of the different linear actuators must be done in a controlled manner, because otherwise no change of orientation is possible. This means that if one actuator 81 exerts a pulling force on the corresponding longitudinal element, the other actuator must behave in a corresponding manner, i.e. exert a smaller pulling force or exert a pushing force so that the total is balanced. The same applies when both sets of actuators are actuated simultaneously. The area of ​​the instrument that contains the linear actuators is the respective actuation zone of the instrument in this embodiment.

[0126] Other robotic embodiments may also be applied.

[0127] The steering mechanism at the proximal end may alternatively be realised by a spherical steering unit or a tiltable disk to which its longitudinal elements are attached. Such implementations are known as such. These may be operated by a human operator or by a robotic device which may itself be controlled by a human operator.

[0128] According to some embodiments, the proximal portion may have a larger diameter, as shown in Fig. 6. The inner cylindrical element 2202 is composed of a first rigid end 2225, a first flexible portion 2224, an intermediate portion 2223, a second flexible portion 2222, and a second rigid end 2221, which is typically used as the operating portion of the instrument, i.e., the proximal portion, in that it serves to steer the opposite end of the unit. The outer cylindrical element 2204 is similarly composed of a first rigid portion 2245, a flexible portion 2244, an intermediate portion 2243, a second flexible portion 2242, and a second rigid portion 2241. The intermediate cylindrical element 2203 also has a first rigid end 2335 and a second rigid end 2331, which in the assembled state are arranged between the corresponding rigid parts 2225, 2245 and 2221, 2241 of the two outer cylindrical elements 2202, 2204, respectively. In the illustrated embodiment, the longitudinal element 2338 is of the type shown in FIG. 4g, but it will be obvious that any of the above types can be used. Up to this point, the construction is comparable to the previously described instruments. The main difference with respect to the above-mentioned embodiments is the use of a set of different diameters for some parts of the instrument. In the embodiment shown in FIG. 6, the parts 2222, 2221, 2331, 2242 and 2241 have a larger diameter than the other parts. In the parts 2223, 2338 and 2243, frustoconical parts are made to connect the parts with smaller diameters to the parts with larger diameters. As shown in FIG. 6, the different parts can be easily assembled by inserting one into the other. However, the main reason for such instruments having different diameters is that by using a larger diameter operating part, the travel at the other end is amplified and when a smaller diameter is used, the travel at the other end is reduced. Depending on the application and its requirements, a larger diameter can be used to have amplified travel and a smaller diameter can be used to have reduced travel and improved accuracy.

[0129] This widening of the instrument with an increasing diameter towards the proximal part can also be applied to instruments with three or more bendable parts, as shown in Fig. 7. In Fig. 7, an instrument with four layers is shown, which is therefore comparable to the instruments of Figs. 4d and 4e, for example, but with the working part of the cylindrical element having a larger diameter compared to the end part for handling, and with a frustoconical part incorporated in zone 155. Due to the larger diameter of the working part at the proximal end, the movement of the handling part at the distal end is amplified when bending, thereby amplifying the movement of the handling head. It is also possible to operate in the opposite direction with the handling part at the distal end having a larger diameter than the working part at the proximal end, reducing the magnitude of the movement and increasing the precision of the movement of the handling head.

[0130] Figures 8a and 8b show an embodiment of a section of an intermediate cylindrical element 102, 103 of the prior art, e.g. WO 2016 / 089202 A1, which comprises breaking elements 7 having the shape of a circle arranged in the gaps 6 formed between adjacent longitudinal elements 4. The breaking elements 7 are attached to each adjacent longitudinal element 4 at the ends of the breaking positions 7.1. These breaking elements hold the adjacent longitudinal elements together during assembly of the device, e.g. preserving their relative order and geometric consistency.

[0131] After assembly of the device, the breaking elements break (fracture) due to a combination of bending and torsional forces caused by rolling of the circular breaking elements 7 along the sides of the longitudinal elements 4. In general, the breaking elements 7 can be designed to have a shape such that one or more of a shear force, bending force and / or torsional force are applied to the breaking location 7.1 of the breaking elements when adjacent longitudinal elements 4 are moved relative to one another.

[0132] In the embodiment of figures 8a and 8b, the longitudinal elements 4 have thinner sections creating gaps 6 and wider sections separated only by small slits 5. The reason is that in a steerable instrument with a rigid intermediate section 12, the longitudinal elements are separated only by small slits 5 along at least a part of their length in the rigid intermediate section and the movement of the longitudinal elements is guided by adjacent longitudinal elements providing for a well controlled movement of the longitudinal elements. The width of the longitudinal elements also provides mechanical strength to the steerable instrument.

[0133] The breakage or destruction of the breaking locations occurs after sliding the different cylindrical elements into each other, so that the breaking elements remain inside the device. As can be seen from figures 8a and 8b, the shape and dimensions of the gaps 6 and the breaking elements 7 limit the relative movement of the adjacent longitudinal elements 4. If the break does not accidentally occur at one of the breaking locations 7.1, the relative movement of the adjacent longitudinal elements is further limited. If a bending force is then applied that exceeds the range set by the dimensions of the gaps 6 and the breaking elements 7, the device may be seriously damaged or even fail. As can be seen from figure 8b, this first causes the breaking element 7 to move and contact one of the longitudinal elements 4 at the edge of the gap 6. If the applied force is large enough, the breaking element 7 is forced to move further by sliding over or under the intermediate cylindrical elements 102, 103 or into the slit 5. Thus, the breaking element 7 may get stuck and obstruct the relative movement of the elements inside the device or otherwise seriously damage the device.

[0134] 9a, 9b and 9c show an embodiment of a steerable instrument flexibility zone as described in prior art WO 2019 / 009710 A1. The inclusion of radial spacer 294e provides distance between cylindrical elements 204, 208 to prevent longitudinal element 282 of middle cylindrical element 206 from jamming, for example, during bending of the instrument flexibility zone.

[0135] As shown in FIG. 9a, the cylindrical element 204 is provided on its wall 296 with a lip shaped portion 294e.

[0136] 9b, in the intermediate cylindrical element 206, the band-like units forming the tangential spacers 275 are held together by spacer portions 294f. In some locations, adjacent longitudinal element portions 282 are separated by free spaces 320 rather than by spacers 275.

[0137] When the intermediate cylindrical element 206 is inserted into the cylindrical element 204, the lip-shaped portions 294e are positioned above the free space 320. Each lip-shaped portion 294e bends inwardly and, while in the bent inward position, extends through the free space 320 and contacts a portion of the cylindrical element 208. Figure 9c shows a longitudinal mounted cross section at the location of such free space 320 when the intermediate cylindrical elements 204, 206, 208 are inserted into one another.

[0138] Assuming that the intermediate cylindrical element 206 has a height h1, the lip shaped portion 294e is bent inwardly over a distance of h3, where h3>h1. Thus, at the location of the bent lip shaped portion 294e, a well-defined radial space between the intermediate cylindrical elements 204 and 208 is created, which is greater than the height h1 of the longitudinal element portion 282. This allows the instrument to move longitudinally even in a situation where it is bent in the flexibility zone.

[0139] However, the embodiment of Figures 9a-9c has several drawbacks: if the lip-shaped portion 294e forming the radial spacer extends through the gap 320 between the tangential spacer 275 and the edge of the longitudinal element portion 284, the lip-shaped portion 294e may contact the flexible zone of the instrument as it bends, thus limiting the extent to which the instrument can be bent. If the lip-shaped portion 294e does not pass through such gap 320, the spacer portion 294f may contact the edge of the longitudinal element portion 284, also limiting the extent to which the instrument can be bent, and / or the tangential spacer 275 may slide up or down the longitudinal element portion 284 or force adjacent longitudinal elements 276 apart, similar to the problems discussed above with respect to Figures 8a, 8b.

[0140] Furthermore, the force applied to bend the lip shaped portion 294e must be applied with great precision, i.e., as radially as possible, as otherwise the lip shaped portion may not bend as intended, resulting in the lip shaped portion 294e not making contact with the cylindrical element 208, thereby not achieving the desired radial spacing, and / or the lip shaped portion 294e abutting one or both of the adjacent longitudinal element portions 282, causing friction during use of the instrument.

[0141] FIG. 10 shows an example of an intermediate portion 12 of an intermediate cylindrical element 1002, 1003 of a steerable instrument having a substantially flexible intermediate portion according to an embodiment of the present invention. The proximal end of the intermediate cylindrical element can be the proximal end shown in FIGS. 4a, 4d, 4e, 4f, 4h, 4i, 6 and 7 or the proximal end shown in FIG. 5. The distal end of the intermediate cylindrical element can be the distal end shown in FIGS. 4a-4i and 5-7. The features have already been described in detail and will not be repeated here. The longitudinal elements 1038 shown in FIG. 10 are connected or attached at their respective ends to actuators within the longitudinal elements or a portion of the longitudinal elements or a portion of the distal end portion and the proximal end in a manner known to those skilled in the art. The longitudinal elements 1038 can be monolithically formed with the longitudinal elements at their respective proximal and distal ends or can be connected or attached thereto during the manufacture of the instrument.

[0142] The intermediate cylindrical elements 1002, 1003 represent an embodiment of the first cylindrical element described in the "Overview" section above.

[0143] In the embodiment shown in FIG. 10, the intermediate cylindrical elements 1002, 1003 include a plurality of longitudinal elements 1038 that follow the intermediate portion of the cylindrical elements 1002, 1003. Via the longitudinal elements 1038, forces can be transferred from the proximal end to the flexible distal zones, thereby controlling the bending of the distal end of the steerable instrument, for example as described in detail above with respect to FIGS. 4-7. When multiple flexible distal zones are provided, these can be individually controlled as described above. Such individual control of bending of the flexible zones can be achieved by the multiple longitudinal elements 1038 being divided into different sets of longitudinal elements, arranged such that each set of longitudinal elements controls one flexible distal zone. Alternatively, one intermediate cylindrical element can be provided for each flexible distal zone.

[0144] For example, as described above with respect to Figure 5, the longitudinal elements may be connected at their proximal ends to linear actuators, whereby bending or deflection of the flexible distal zone of the instrument is computer or robotically controlled. Alternatively, as also described above, a force may be applied to the longitudinal elements by bending or deflecting one or more proximal flexible zones. As an alternative, a spherical steering unit or a tiltable disk may be provided to which the longitudinal elements are attached, which is manipulable by the robotic instrument.

[0145] The longitudinal elements 1038 extend in a longitudinal direction 1008, which may be parallel to the cylindrical axis 1010 as in the embodiment of Figure 10. Alternatively, the longitudinal direction 1008 may be arranged helically with respect to the cylindrical axis 1010, for example as shown in Figure 4i.

[0146] The longitudinal elements 1038 are arranged such that there are gaps or spaces 1006 between adjacent longitudinal elements 1038. In one embodiment, the longitudinal elements have uniform dimensions throughout the middle portion and are evenly distributed around the circumference of the cylindrical element such that all of the spaces 1006 have the same dimensions.

[0147] The tangential spacers 1007, 1017 are disposed in the gaps 1006 between adjacent longitudinal elements 1038. The longitudinal elements 1038 and the tangential spacers 1007, 1017 are longitudinally movable relative to each other. Preferably, the longitudinal elements 1038 and the tangential spacers 1007, 1017 are not attached to each other and do not limit their respective movements in the longitudinal direction. The tangential spacers 1007, 1017 maintain the tangential distance between adjacent longitudinal elements 1038 while providing sufficient tangential support to the longitudinal elements 1038, thereby providing mechanical strength and stability to the device.

[0148] 10 shows that the tangential spacers 1007, 1017 are arranged to maintain the tangential distance between two adjacent longitudinal elements 1038, but the tangential spacers according to the invention can also be applied between one longitudinal element 1038 and another part of the cylindrical elements 1002, 1003, in which case the longitudinal element 1038 can move tangentially with respect to the other part of the cylindrical elements 1002, 1003. Thus, the tangential spacers 1007, 1017 are arranged to maintain the tangential distance between this longitudinal element 1038 and the other part.

[0149] 10 shows an embodiment in which a plurality of longitudinal elements 1038 are distributed around the circumference of the cylindrical element, but this is not essential to the invention. In some embodiments, the intermediate cylindrical element 1002, 1003 comprises at least one longitudinal element 1038 (i.e. possibly only one longitudinal element), the other part of the cylindrical element substantially adjacent or next to the at least one longitudinal element extends in the longitudinal direction of the tube, and the other part of the cylindrical element does not form a longitudinal element itself. The tangential spacer, i.e. at least one tangential spacer, is arranged tangentially adjacent to the at least one longitudinal element in the gap between the longitudinal element and the other part of the cylindrical element.

[0150] In the embodiment of Fig. 10, a number of tangential spacers 1007 are arranged in the gap 1006. The number of tangential spacers 1007, their shape and size as well as the distance between tangential spacers 1007 arranged in the same gap 1006 depends for example on the desired mechanical properties of the intermediate cylindrical elements 1002, 1003. Preferably, as shown in Fig. 10, the tangential spacers 1007 have an elongated shape and extend in the longitudinal direction 1008.

[0151] The longitudinal elements 1038 preferably have the same width w throughout their extent in the middle, so that the relative movement between the tangential spacers 1007, 1017 and the adjacent longitudinal elements 1038 is not limited by the wider parts of the longitudinal elements 1038. This reduces the risk of the tangential spacers sliding above or below the longitudinal elements 1038.

[0152] During assembly of the instrument, the tangential spacers 1007, 1017 may be attached to the adjacent longitudinal elements 1038 by breakable elements 1007a, 1017a which are broken or destroyed by moving the adjacent longitudinal elements 1038 in opposite longitudinal directions with respect to each other after assembly of the instrument, as described in the applicant's WO 2016 / 089202 A1 and PCT / NL2022 / 050318. This provides stability of the intermediate cylindrical element and geometric consistency of the longitudinal elements 1038 during assembly of the instrument.

[0153] In the embodiment of Figure 10, two types of tangential spacers 1007, 1017 are provided. As can be seen, a first type of tangential spacer 1007 is disposed in every other gap 1006 when viewed tangentially. In one example, radial spacers 1094 are provided between these tangential spacers 1007, as shown in Figures 11a and 11b. In the remaining every other gap 1006, a second type of tangential spacer 1017 is disposed, which extends through substantially the entire length of the gap 1006 and is not attached to at least one of the proximal and distal ends.

[0154] According to the invention, the tangential spacer 1007 is provided with one or more openings 1029. The tangential spacer 1017 may also be provided with one or more such openings 1029. This is shown diagrammatically in figure 10 and in more detail for the tangential spacer 1007 in figure 14.

[0155] 11a and 11b show how an inwardly curved lip 1094 from the outer cylindrical element 1004 into the gap 1006 at the longitudinal end of the tangential spacer 1007 and / or into the opening 1029 of the tangential spacer 1007, 1017 can limit movement of the tangential spacer 1007, 1017.

[0156] FIG. 11a shows cylindrical elements 1002, 1003 coaxially aligned with an outer cylindrical element 1004. The outer cylindrical element 1004 represents an embodiment of the second cylindrical element described in the Overview. Like the intermediate cylindrical elements 1002, 1003, the outer cylindrical element 1004 also includes a proximal end, a distal end including at least one flexible distal portion, and an intermediate portion between the proximal and distal ends, which mate with corresponding portions of the intermediate cylindrical element to provide a steerable instrument. As before, FIGS. 11a and 11b show only a portion of the intermediate portion of the cylindrical elements.

[0157] As can be seen, a plurality of radial spacers 1094 are provided which are attached to or formed as part of the outer cylindrical element 1004. The radial spacers 1094 extend radially inwardly and protrude into and actually extend through the gaps 1006 formed between adjacent longitudinal elements 1038 of the intermediate cylindrical elements 1002, 1003. Preferably, the radial spacers 1094 are formed by lip shaped portions formed in the wall of the outer cylindrical element 1004, as will be described in more detail with respect to Figures 15-19.

[0158] Figure 11b shows a cross-sectional view of Figure 11a, where it can be seen that radial spacers 1094 are provided at each of the longitudinal ends of the tangential spacers 1007 and extend through the gaps 1006.

[0159] As described with respect to FIGS. 12 and 13, radial spacers 1094 may set the distance between the outer cylindrical element 1004 and the inner cylindrical element 1001 .

[0160] 11a and 11b, the radial spacer 1094 restricts or limits the movement in both directions along the extent of the longitudinal element 1036 relative to the second cylindrical element of the tangential spacer 1007. The longitudinal elements 1038 can move relative to each other, thereby allowing the bendable portions of the cylindrical elements to bend or flex so that the restriction or narrowing formed by the tangential spacer 1007 does not contact the edge of a portion of the longitudinal element 1038.

[0161] FIG. 12 shows an example of an inner cylindrical element 1001. In FIG. 12, only the middle part of the inner cylindrical element 1001 is shown, similar to FIGS. 10, 11a and 11b. Similar to the outer and middle cylindrical elements 1004, 1002, 1003, the inner cylindrical element 1001 includes a proximal end, a distal end including at least one flexible distal portion, and a middle part extending between the proximal and distal ends. In the assembled device, these various parts or portions mate with corresponding parts or portions of the other cylindrical elements of the device. The inner cylindrical element 1001 may represent an embodiment of the third cylindrical element described in the "Overview" above.

[0162] The inner cylindrical element 1001 is provided with a number of openings 1096 which, after assembly of the instrument, cooperate with the radial spacers 1094 so that the tips of the radial spacers extend into the openings 1096, as shown in Figures 13a, 13b. The openings 1096 are formed as through holes in the wall of the inner cylindrical element 1001, as this makes manufacturing easier and allows the radial spacers 1094 to better engage or lock into the openings 1096. However, alternatively, they may be formed as recesses, thereby forming thinner portions of the wall of the inner cylindrical element.

[0163] Figures 13a, 13b show an inner cylindrical element 1001 slid into and coaxially aligned with the intermediate and outer cylindrical elements 1002, 1003, 1004 shown in Figures 11a, 11b. Figure 13a shows a perspective view of a cross section taken along the cylindrical axis, and Figure 13b shows a cross section of the assembled inner, intermediate and outer cylindrical elements. In Figures 11 and 13, only one intermediate cylindrical element is shown, but it should be understood that multiple such intermediate cylindrical elements may be provided, similar to the embodiment shown in Figures 4a-4e.

[0164] 13a and 13b, the radial spacers 1094 protrude into openings 1096 formed in the inner cylindrical element 1001. By this arrangement, the inner and outer cylindrical elements 1001, 1004 are fixed axially, radially and tangentially with respect to each other.

[0165] In an alternative embodiment, the inner cylindrical element 1001 may not have the opening 1096, in which case the radial spacer 1094 is positioned to abut against the inner surface of the wall of the inner cylindrical element 1001 and to fix the outer cylindrical element 1004 relative to the inner cylindrical element 1001, at least to some extent, by friction between the radial spacer 1094 and the inner cylindrical element 1001.

[0166] The radial spacer 1094 provides a distance between the inner cylindrical element 1001 and the outer cylindrical element 1004. The radial spacer 1094 has a radial dimension such that this distance is greater than the radial thickness of the longitudinal element 1038 and the tangential spacers 1007, 1017. This may prevent the longitudinal element 1038 from getting pinched or jammed between the inner and outer cylindrical elements 1001, 1004 when the middle portion of the device is bending or flexing.

[0167] In the embodiment of Figure 13a, the tangential spacer 1007 is confined within a cage-like structure formed by the radial spacer 1094, the inner cylindrical element 1001, the outer cylindrical element 1004 and the adjacent longitudinal element 1038, and is not connected or attached to any of these elements. Within this cage, the tangential spacer 1038 is free to move and can be said to be floating.

[0168] 14 shows a tangential spacer 1007 according to an embodiment of the invention. The movement of the tangential spacer 1007 in both the longitudinal and tangential directions of the instrument is constrained by one or more radial spacers 1094 as described above. The tangential spacer 1007 may be free floating at one or both of its longitudinal ends, i.e., it is not attached or connected to other parts of the cylindrical elements 1002, 1003. The tangential spacer 1007 is provided with an opening 1029, which in an embodiment has a predetermined length in the longitudinal direction and a predetermined width w in the tangential direction. a In the assembled instrument, the radial spacers 1094 protrude through the openings 1029 such that movement of the tangential spacers 1007 relative to the other cylindrical elements 1004 in both the longitudinal and tangential directions is limited by the single radial spacer 1094 protruding through the openings 1029. The radial spacers 1094 have a tangential radial spacer width w, as viewed tangentially when the tangential spacer 1007 is disposed in the instrument. rs The opening width w of the opening 1029 a 90% of <w rs <100%, preferably 95% <w rs <100%, even more preferably 98% <w rs <100%. Radial spacer width w rs 15-17, which are described below. The tangential spacer 1007 can only move a small, well-defined maximum amount in the tangential direction relative to the cylindrical element 1004. However, alternatively, the radial spacer 1094 can move only a small, well-defined maximum amount in the tangential direction relative to the cylindrical element 1004. aA radial spacer width w equal to or slightly larger than, for example, up to 5% rs 1029, so that when the radial spacer 1094 bends into the opening 1029, it clamps the tangential spacer 1007. It can be seen that since the movement of the tangential spacer 1007 is constrained in the tangential direction, other parts of the cylindrical elements 1002, 1003, including one or more longitudinal elements 1038, are also constrained in their tangential movement with respect to the cylindrical element 1004. The radial spacer 1094 may be in contact with the cylindrical element 1001, but does not have to be. For example, the number of radial spacers 1094 and corresponding optional openings 1096 of the inner cylindrical element 1001 can be adjusted to the number of tangential spacers 1007. The tangential spacer 1007 can be provided with a number of openings 1029 through which the radial spacers 1094 protrude.

[0169] In an embodiment, the tangential spacer 1017 may also be provided with one or more openings 1029, through which the radial spacer 1094 extends in the same manner and with the same technical effect as described with respect to Fig. 14. Furthermore, the embodiment of Fig. 14 may be combined with one of Figs. 11A-13B, whereby the lip 1094 extending into the opening 1029 constrains the longitudinal and tangential movements of the tangential spacer 1007 and / or 1017, and the lip 1049 extending into the gap 1006, for example, maintains the radial distance at least between the cylindrical elements 1001 and 1004.

[0170] 15-17 show various embodiments of lip shaped portions 1097, 1098, 1099 formed in the wall of a cylindrical element for use as a radial spacer, such as the radial spacer 1094 of the previous embodiment. The lip shaped portions may be formed by laser cutting one or more slots in the wall of the cylindrical element. The resulting radial spacer is preferably flexible and has at least some degree of flexibility or resilience with respect to the cylindrical element from which it is formed.

[0171] Advantageously, the lip shaped portions 1097, 1098, 1099 are formed in the outer cylindrical element 1004, whereby the radial spacers can be formed by bending each of these lip shaped portions radially inwards after the instrument is assembled. Alternatively, it can also be formed in the inner cylindrical element 1001, which can be bent radially outwards to form the radial spacers.

[0172] In addition to forming radial spacers 1094 used in the intermediate section 12 of the device, the lip shaped portions 1098, 1099 shown in Figures 16 and 17 may be used to form radial spacers provided in the distal flexibility zones 16, 17 and, if present, the proximal flexibility zones 14, 15 of the device, thereby replacing the lip shaped portion 294e of Figures 9a-9c.

[0173] The lip shaped portion 1097 shown in Figure 15 corresponds substantially to the lip shaped portion 294f shown in Figures 9a to 9c.

[0174] 16 and 17 show lip shaped portions 1098, 1099 according to an embodiment of the present invention, which represent a further development of the prior art lip shaped portions.

[0175] As shown in FIGS. 16 and 17, the lip shaped portions 1098 , 1099 are attached to or form a connection with the wall of the second cylindrical element 1004 via a beam 1100 having a beam axis 1101 .

[0176] 16 and 17, the beam axis 1101 extends in a direction substantially perpendicular to the cylindrical axis 1010 (longitudinal direction) of the second cylindrical element 1004. This is advantageous for embodiments of the steerable instrument in which the longitudinal elements 1038 extend in a direction parallel to the cylindrical axis in the intermediate region, i.e. the longitudinal direction 1008 of the longitudinal elements 1038 is along the cylindrical axis.

[0177] Alternatively, the beam axis 1101 may be oriented at different angles relative to the cylindrical axis 1010, for example, depending on the direction in which the longitudinal elements 1038 extend throughout the intermediate region. As previously mentioned, in some embodiments, the longitudinal elements may be arranged to form at least a helix or extend at least in a spiral direction relative to the cylindrical axis. In such embodiments, the angle may be slightly less than 90 degrees. However, it will be appreciated that the beam axis 1101 may extend perpendicular to the cylindrical axis 1010 even when the longitudinal elements 1038 extend along a helical path.

[0178] In summary, the beam axis 1101 may extend in a direction substantially perpendicular to the direction in which the longitudinal element 1038 extends at the location of the beam axis in the intermediate cylindrical element with which the outer cylindrical element 1004 is intended to be used.

[0179] The lip shaped portions 1098, 1099 are defined by a first slot 1102 formed in the wall of the cylindrical element 1004. This slot 1102 extends on all sides of the periphery of the lip shaped portions 1098, 1099 except where the lip shaped portions are attached to the wall via the beam 1100. In addition, a first slot portion 1102b extends on one side of the beam 1100 in a direction substantially parallel to the beam axis 1101 on both sides of the lip shaped portions 1098, 1099. The beam 1100 is defined by a second slot 1103 provided in the wall of the second 1004, the second slot 1103 extending on the opposite side of the beam 1100 in a direction substantially parallel to the beam axis 1101.

[0180] The slots 1102, 1103 may advantageously be formed by laser cutting the wall of a cylindrical element.

[0181] This configuration of the beam 1100 defined by the lip shaped portions 1098, 1099 and the slots 1102, 1003, which form the attachment to the cylindrical element 1004, allows the radial bending of the cylindrical element of the lip shaped portion to be defined with great precision. When a force is applied radially to the lip shaped portion, it bends about the beam axis 1101.

[0182] In the embodiment of Fig. 17, the lip shaped portion 1099 comprises a first portion 1099a having a first width in a direction substantially parallel to the beam axis 1101 and a second portion 1099b having a second width smaller than the first width. The first portion 1099a is positioned closest to the beam 1100 and forms an attachment thereto, and the second portion 1099b forms an outer tip of the lip shaped portion 1099. The second portion 1099b is advantageously used to engage, e.g. be inserted into, an opening or recess 1096 of another, e.g. inner cylindrical element 1001, arranged coaxially with the outer cylindrical element 1004, as shown in Figs. 13a, 13b.

[0183] Figures 18a-18c show an embodiment of a part of an outer cylindrical element 1004 provided with a plurality of lip-shaped portions 1099 according to the embodiment shown in Figure 17. In the embodiment of Figures 18a-18c, the beam axis 1101 is oriented perpendicular to the cylinder axis 1010, but as mentioned above, the orientation is set depending on the orientation of the longitudinal elements in the intermediate region. Figure 18a shows the lip-shaped portion before bending. As can be seen in this figure, in this embodiment, the beam 1100 is symmetrical about the beam axis 1101 and the lip-shaped portion is symmetrical about the cylinder axis 1010. In other embodiments, as mentioned above, the beam axis can be oriented at a different angle other than perpendicular to the cylinder axis 1010. In this case, the lip-shaped portion is symmetrical about an axis extending perpendicular to the beam axis.

[0184] As shown in Figures 18b and 18c, the lip shaped portion 1099 is bent radially inwards to form a radial spacer 1094. By bending the lip shaped portion as shown in Figure 18b, a straight, axisymmetric radial spacer is obtained. As can be seen, the radial spacer is symmetric about the radial axes 1105, 1106.

[0185] It should be noted that the number and distribution of the lip-shaped portions and radial spacers shown in Figures 18a-18c are merely examples provided for illustration purposes, and the number of lip-shaped portions / radial spacers and their distribution along the circumference of the cylindrical element and along the axial direction of the cylindrical element are set depending on various properties to be realized in the assembled steerable device, such as flexibility and / or mechanical strength of the intermediate region.

[0186] Figure 19 shows a part of an outer cylindrical element 1004 provided with a lip-shaped portion, assembled with an inner cylindrical element 1001. A radial spacer 1094 engages with an opening 1096 provided in the inner cylindrical element 1001. To clarify the illustration of the locking principle of the inner and outer cylindrical elements with respect to one another, one or more intermediate cylindrical elements 1002, 1003 have been omitted in Figure 19.

[0187] With respect to the embodiment shown in Figures 18 and 19, although it has been described that the lip-shaped portion forming the radial spacer is formed on the outer cylindrical element 1004, this is not necessarily the case and the lip-shaped portion forming the radial spacer may alternatively be formed on the inner cylindrical element 1001, in which case the radial spacer is then formed by bending the lip-shaped portion in a radially outward direction so as to engage with the outer cylindrical element 1004.

[0188] A steerable instrument may be formed by providing an inner cylindrical element 1001, an outer cylindrical element 1004 and one or more intermediate cylindrical elements 1002, 1003 as previously described, thereby providing the inner cylindrical element 1001 shown in Figure 12, one or more intermediate cylindrical elements 1002, 1003 shown in Figure 10 and the outer cylindrical element shown in Figures 11a, 11b, 18a, 18b and 18c.

[0189] These cylindrical elements 1001-1004 are then coaxially aligned by sliding them into each other and aligning them along the direction of the cylindrical axis such that the corresponding flexible and bending portions and regions of the various cylindrical elements are aligned. The lip-shaped portion 1094 formed in the outer cylindrical element is then bent radially inwards by applying a force applied perpendicularly to the lip-shaped portion of the wall, so that the lip-shaped portion bends radially inwards and eventually protrudes into the gap 1006 or opening 1029 (FIG. 14) and, optionally, engages with an opening 1096 provided in the wall of the inner cylindrical element 1001.

[0190] After assembly of the device, the releasable attachments of the tangential spacers 1007, 1017 are released. The releasable attachments are preferably provided by breakable elements 1007a, 1017a, which break by bending the device in different directions after its assembly. Alternatively, such breakable elements can be broken by energy, e.g. laser, beam or by fatigue.

[0191] By providing a cylindrical element having an intermediate portion according to one or more of the embodiments described herein above with respect to Figures 10-19, it is possible to achieve a steerable instrument having a flexible intermediate portion 12, which is flexible over substantially its entire extent, at least in the area where the instrument is inserted into the body. In particular, this provides a steerable instrument suitable for applications such as colonoscopy and / or gastroscopy and / or surgery.

[0192] The scope of the present invention is not limited to the above examples, and it will be apparent to those skilled in the art that several modifications and improvements thereof are possible without departing from the scope of the present invention defined in the appended claims. Although the present invention has been illustrated and described in detail in the drawings and description, such illustrations and descriptions are to be considered as illustrative or exemplary only and not restrictive. The present invention is not limited to the disclosed embodiments, but includes all combinations that may provide the benefits of the disclosed embodiments.

[0193] Variations of the disclosed embodiments can be understood and implemented by those skilled in the art by studying the drawings, the description and the appended claims in the practice of the claimed invention. In the description and claims, the term "comprises" does not exclude other elements, and the indefinite articles "a" or "an" do not exclude the plural. Indeed, this should be interpreted as meaning "at least one". The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage. Reference signs in the claims should not be interpreted as limiting the scope of the invention. Features of the above-mentioned embodiments and aspects may be combined, unless such combination results in an obvious technical contradiction.

Claims

1. A steerable instrument (10, 2201) for endoscopic and / or invasive applications in surgery or the like, comprising: a first cylindrical element (1002, 1003) including a first proximal end, a first distal end including at least one first flexible distal portion and a first intermediate portion between said first proximal end and said first distal end, and at least one longitudinal element (1038) arranged to transmit a force from said first proximal end to said at least one first flexible distal portion and thereby control bending of said at least one first flexible distal portion; at least one tangential spacer (1007, 1017) arranged tangentially adjacent to said at least one longitudinal element (1038) in a gap (1006) between said at least one longitudinal element (1038) and another portion of said first cylindrical element (1002, 1003); a second cylindrical element (1004) arranged coaxially with the first cylindrical element (1002, 1003) and including a second proximal end corresponding to and substantially aligned with the first proximal end, the first distal end, and the first intermediate portion of the first cylindrical element, respectively, a second distal end including at least one second flexible distal portion, and a second intermediate portion between the second proximal end and the second distal end; at least one radial spacer (1094) attached to said second cylindrical element and projecting into an opening (1029) of said tangential spacer (1007, 1017), whereby movement of said tangential spacer (1007, 1017) in both longitudinal and tangential directions of said steerable instrument is limited by said at least one radial spacer (1094); and optionally at least one further radial spacer (1094) attached to said second cylindrical element and projecting into said gap (1006) at a longitudinal end of said at least one tangential spacer (1007, 1017); A steerable instrument (10, 2201) comprising:

2. 2. The steerable instrument of claim 1, wherein the first cylindrical element is a first cylindrical tube, and both the at least one longitudinal element (1038) and the at least one tangential spacer (1007, 1017) are part of the first cylindrical tube.

3. The steerable instrument of claim 1 or 2, wherein the second cylindrical element is a second cylindrical tube.

4. 4. The steerable instrument of claim 3, wherein the at least one radial spacer (1094) and the at least one further radial spacer (1094) are formed by a lip-shaped portion (1097, 1098, 1099) of a second cylindrical tube protruding from the second cylindrical tube.

5. The lip-shaped portions (1097, 1098, 1099) have a lip-shaped portion width (w ｒｓ , W ｒｓ１ ), and the opening (1029) has an opening width (w ａ 5. The steerable instrument of claim 4, further comprising a lip shaped portion having a width that is either smaller than the opening width or configured such that when bent into the opening it clamps the tangential spacer.

6. the lip-shaped portion (1098, 1099) is formed in a wall of the second cylindrical tube and is attached thereto via a beam (1100) having a beam axis (1101) extending substantially perpendicular to the longitudinal direction (1008); the lip shaped portion is defined by a first slot (1102) formed in the wall, the first slot extending around the periphery of the lip shaped portion except where the lip shaped portion is attached to the beam (1100); the first slot (1102) further extends (1102b) on either side of the beam in a direction substantially parallel to the beam axis (1101) on either side of the lip-shaped portion; 6. The steerable instrument of claim 4 or 5, wherein the beam is further defined by a second slot (1103) provided in the wall on another side of the beam (1100) in a direction substantially parallel to the beam axis (1101).

7. 7. The steerable instrument of claim 1, wherein, in the first intermediate portion, the at least one longitudinal element (1038) has a length in the longitudinal direction (1008) and a width in a direction substantially perpendicular to the longitudinal direction, the width being substantially constant throughout the length.

8. a third cylindrical element (1001) arranged coaxially with the first cylindrical element (1002, 1003) and the second cylindrical element (1004), the first cylindrical element is disposed between the second cylindrical element and the third cylindrical element; The steerable instrument of any one of claims 1 to 7, wherein the at least one radial spacer (1094) or the at least one further radial spacer (1094) is at least one of: arranged to abut against the third cylindrical element (1001), engaged with the third cylindrical element, and attached to the third cylindrical element.

9. 9. The steerable instrument of claim 8, wherein the third cylindrical element (1001) is a third cylindrical tube provided with at least one recess or opening (1096), and the at least one radial spacer (1094) or the at least one further radial spacer (1094) protrudes into the at least one recess or opening (1096).

10. 10. The steerable instrument of claim 9, wherein the radial spacer (1094) or the at least one further radial spacer (1094) includes a first portion (1099a) having a first width and a second portion (1099b) having a second width smaller than the first width, the second portion protruding into the recess or opening (1096).

11. The steerable instrument of any one of claims 8 to 10, wherein the at least one radial spacer (1094) or the at least one further radial spacer (1094) forms a distance between the second cylindrical element (1004) and the third cylindrical element (1001) in the radial direction that is greater than a thickness between the at least one longitudinal element (1038) and the at least one tangential spacer (1007, 1017) in the radial direction.

12. The steerable instrument of any one of claims 8 to 11, wherein the third cylindrical element (1001) comprises a third proximal end portion corresponding to and substantially aligned with the first proximal end portion, the first distal end portion and the first intermediate portion of the first cylindrical element (1002, 1003), respectively, a third distal end portion including at least one third flexible distal portion, and a third intermediate portion between the third proximal end portion and the third distal end portion.

13. The steerable instrument of any one of claims 8 to 12, wherein the third cylindrical element (1001) forms an inner cylindrical element, the first cylindrical element (1002, 1003) forms an intermediate cylindrical element, and the second cylindrical element (1004) forms an outer cylindrical element.

14. A steerable instrument as claimed in any one of claims 1 to 13, wherein the first cylindrical element (1002, 1003), the second cylindrical element (1004) and, if present, the third cylindrical element (1001) are provided with one or more flexible portions throughout their entire length.

15. The steerable instrument of any one of claims 1 to 14, comprising a plurality of tangential spacers (1007, 1017) and a plurality of radial spacers (1094) and a plurality of longitudinal elements (1038), at least one tangential spacer and at least one radial spacer being provided between each adjacent longitudinal element (1038).

16. a plurality of tangential spacers (1007, 1017), a plurality of radial spacers (1094) and a plurality of longitudinal elements (1038); the plurality of longitudinal elements (1038) includes a first longitudinal element, a second longitudinal element, and a third longitudinal element; In the first intermediate portion, a first gap is formed between the first longitudinal element and the second longitudinal element; a second gap is formed between the second longitudinal element and the third longitudinal element; At least one tangential spacer (1007) and at least one radial spacer (1094) are provided within the first gap; The steerable instrument of any one of claims 1 to 14, wherein an extended tangential spacer (1017) is provided within the second gap, the extended tangential spacer extending substantially throughout the entire second gap.

17. A cylindrical element for use in a steerable instrument (10, 2201), the cylindrical element extending along a cylindrical axis and including a wall, at least one lip-shaped portion (1098, 1099) being formed in said wall, the lip shaped portion is formed in the wall and attached thereto via a beam (1100) having a beam axis (1101), the beam axis being disposed at an angle to the cylinder axis (1010); the lip shaped portion is defined by a first slot (1102) formed in the wall, the first slot extending around the periphery of the lip shaped portion except where the lip shaped portion is attached to the beam; the first slot further extends (1102b) on either side of the beam in a direction substantially parallel to the beam axis (1101) on either side of the lip-shaped portion; The beam is further defined by a second slot (1103) provided in the wall on another side of the beam (1100) in a direction substantially parallel to the beam axis.

18. The lip shaped portion (1099) has a first width (w ｒｓ１ ) in a direction substantially parallel to the beam axis, and a second width (w ｒｓ２ 18. The cylindrical element of claim 17, further comprising a second portion (1099b) having a width (1099b) of at least one of the first and second widths, the first portion being disposed between the beam (1100) and the second portion, the second width being smaller than the first width.

19. 19. A cylindrical element according to claim 17 or 18, wherein the lip shaped portion (1098, 1099) is symmetrical with respect to one or both of the beam axis (1101) and an axis substantially perpendicular to the beam axis.

20. A cylindrical element according to any one of claims 17 to 19, wherein the beam axis extends in a direction substantially perpendicular to the cylinder axis (1010).

21. A method of manufacturing a cylindrical element for use in a steerable instrument (10, 2201), said cylindrical element (1004) extending in the direction of a cylindrical axis (1010), said method comprising: - providing a piece of material for forming the wall of said cylindrical element, forming a first slot (1102) in said material, whereby at least one lip shaped portion (1098, 1099) is formed in said material and attached thereto via a beam (1100) having a beam axis (1101), said first slot extending around said lip shaped portion except where said lip shaped portion is attached to said beam (1100) and further extending (1102b) on either side of said lip shaped portion in a direction substantially parallel to said beam axis (1101); forming a second slot (1103) in said wall, said second slot extending in a direction substantially parallel to said beam axis (1101) on another side of said beam (1100); and wherein after said manufacturing, said one or more lip shaped portions are located within said wall of said cylindrical element.

22. 22. The method of claim 21, wherein the beam axis extends in a direction at an angle greater than 0 degrees relative to the cylinder axis (1010).

23. 23. The method of claim 21 or 22, wherein the beam axis (1101) extends in a direction substantially perpendicular to the cylinder axis (1010).

24. 1. A method of manufacturing a steerable instrument (10, 2201) for endoscopic and / or invasive applications in surgery or the like, comprising the steps of: - providing a first cylindrical element (1002, 1003) comprising a first proximal end, a first distal end comprising at least one first flexible distal portion and a first intermediate portion between said first proximal end and said first distal end, forming at least one longitudinal element (1038) extending between said first proximal end and said first distal end and arranged to transmit forces from said first proximal end to said at least one first flexible distal portion and thereby control bending of said at least one flexible distal portion; - forming at least one tangential spacer (1007, 1017) tangentially adjacent to said at least one longitudinal element (1038), said at least one tangential spacer being tangentially attached to said at least one longitudinal element by means of at least one releasable attachment (1007a, 1017a), - providing a second cylindrical element (1004) comprising a second proximal end, a second distal end comprising at least one second flexible distal portion and a second intermediate portion between said second proximal end and said second distal end, forming at least one lip-shaped portion (1097, 1098, 1099) defined by a first slot (1102) in the second wall of said second cylindrical element (1004); - providing a third cylindrical element (1001) comprising a third proximal end, a third distal end comprising at least one third flexible distal portion and a third intermediate portion between said third proximal end and said third distal end, - sliding the cylindrical elements into each other, whereby the cylindrical elements are substantially coaxially aligned; - applying a force to said at least one lip-shaped portion (1097, 1098, 1099) in a direction substantially perpendicular to said second wall of said second cylindrical element (1004), thereby bending said lip-shaped portion radially. Including, whereby, after bending, said at least one lip-shaped portion forms at least one radial spacer (1094) protruding into the opening (1029) of said tangential spacer (1007, 1017); and Whereby, after the releasable attachment portions (1007a, 1017a) are released, movement of the tangential spacers (1007, 1017a) along both the longitudinal direction (1008) and the tangential direction of the steerable instrument is limited by the at least one radial spacer (1094).

25. 25. The method according to claim 24, wherein the third cylindrical element (1001) is provided with at least one opening or recess (1096) in a third wall of the third cylindrical element (1001), and after the bending, the lip-shaped portion (1099) engages with the opening or recess (1096).

26. The lip-shaped portion (1099) forming said first slot (1102), whereby said lip shaped portion is attached thereto via a beam (1100) formed in said second wall and having a beam axis (1101), said first slot extending around said lip shaped portion except where said lip shaped portion is attached to said beam, and further extending (1102b), on one side of said beam, in a direction substantially parallel to said beam axis (1101) on either side of said lip shaped portion (1099); forming a second slot (1103) in said wall, said second slot extending in a direction substantially parallel to said beam axis (1101) on another side of said beam (1100); is formed by The lip shaped portion (1099) has a first width (w ｒｓ１ ) in a direction substantially parallel to the beam axis, and a second width (w ｒｓ２ and a second portion (1099b) having a width greater than or equal to the first width, the first portion being disposed between the beam and the second portion, the second width being less than the first width; 26. The method of claim 25, wherein the second portion engages with the opening or recess (1096) of the third cylindrical element (1001).

27. The method according to any one of claims 24 to 26, further comprising the step of releasing said at least one releasable attachment (1007a, 1017a) of said at least one tangential spacer (1007, 1017).

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