US20200275983A1 - Steerable tube - Google Patents

Abstract

A steerable tube (100), comprising a hollow elongate tubular member (1) having a proximal end (2), distal end (3), a wall surface disposed between said proximal (2) and distal end (4), a bend-resistive zone (6) flanked by a proximal bendable zone (4) that forms a controller and a distal bendable zone (5) that forms an effector that moves responsive to movements of the controller, whereby the wall of the tubular member (1) in the bend-resistive zone (6) comprises a structure that is a plurality of longitudinal slits (7), forming a plurality of longitudinal strips (8, 8′), the wall of the tubular member (1) in the proximal bendable zone (4) and the distal bendable zone (5) comprises a structure that is a plurality of longitudinal wires (9, 9′, 10, 10′), at least one strip (8) is in connection with a wire (9) in the proximal bendable zone (4) and a wire (10) in the distal bendable zone (5), such that translation by said wire (9) in the controller is transmitted via the strip (8) to said wire (10) in the effector, a proximal annular region (11) of the tubular member (1), proximal to the proximal bendable zone (4) to which the proximal wires (9) are anchored, a distal annular region (12) of the tubular member (1) distal to the distal bendable zone (5) to which the distal wires (10) are anchored.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 13/787,538, filed Mar. 6, 2013, which is a divisional of U.S. patent application Ser. No. 12/866,003 filed Aug. 3, 2010, which is the U.S. National Phase under 35 U.S.C. § 371 of International Application PCT/EP2009/051294, filed Feb. 5, 2009, which claims priority to EP 08151060.4, filed Feb. 5, 2008. The contents of these priority applications are hereby incorporated herein in their entirety.
FIELD OF THE INVENTION
• The invention relates to a steerable tube having enhanced control and simplified construction, which can be used in high-precision or medical applications.
BACKGROUND OF THE INVENTION
• The invention relates to an instrument for high-precision mechanical applications or for medical applications (e.g. surgery, endovascular procedures, or for use as an endoscope) of a minimally invasive nature, comprising a hollow tubular member (1) having a proximal bendable zone (4) that forms a controller head, a distal bendable zone (5) that forms an effector—a steerable tip—and flexes responsive to movements of the controller, and, a bend-resistive zone (6) between the aforementioned zones (4,5), that transmits movements of the controller to the effector. The member is preferably formed from one or more substantially solid walled tubes. The high-precision instrument find applications where exquisite, remote movements in confined spaces are needed, such as in medical applications, and in the inspection and repair of encased devices such as engines, pipelines, valves and other mechanical systems.
• The notion an instrument having a steerable tip is known in the art. For instance, WO 03/037416 describes a mechanism that deflects portions of a flexible body such as a catheter in more than one direction in a single plane, as well as in more than one plane by use of a pullwire. In order to control the deflection of the distal end, many designs incorporate one or more steering cables. Mostly these cables are fed through guide-sleeves located in the wall of the tube or in its lumen. These guide-sleeves that hold the steering cables in place are bulky and add to the cross-section of the wall.
• For example, US-A-2006/0178556 (SeeFIGS. 1A and 1C), describes a steerable device having a ring of longitudinally extending cables connecting to the head, which cables are fixedly secured in the radial direction. A disadvantage of this instrument is, however, that the cables are fed through guide-sleeves provided in the longitudinal direction of the cables, which increase the diameter of the instrument.
• A system to omit these sleeves has been described in WO 02/13682 (seeFIGS. 1B and 1D) which discloses a steerable device also of a ring of cables comprising longitudinally extending cables connected to the head, which cables are fixedly secured in the radial direction. Instead of the cables being fed through guide-sleeves as in US-A-2006/0178556, they are disposed side by side so filling the space where the guide sleeves would otherwise be. A disadvantage of this system is the high construction cost for devices where lumen diameters need to be maximised for a given outer diameter—i.e. the walls made thin which is a requirement for most applications. A rapid increase in the number of steering wires is seen when increasing the internal diameter while maintaining a thin wall, for example, 25 steering cables of 0.2 mm for a lumen of 1 mm diameter. Furthermore, the alignment and correct pre-tensioning of a large number of narrow diameter wires represents an enormous technical challenge. Further it is anticipated that the wires of narrowed diameter may slip circumferentially within the sleeve, and tangle or wear.
• It remains challenging to make an adequate affixation with the head and tip. Standard affixation techniques include soldering, clamping, crimping, use of small bolts, glue, knotting, cable U-turns through rigid termination disk or laser-welding. Mostly these affixation techniques result in bulky joints and some of them even weaken the wires.
• Additionally, a compression spring is used in the art to pre-stress the tip, however, this reduces its torsion and bending stability, meaning the tip can readily be deflected from a bent position by the application of an external force to the tip. Moreover, axial compression, for example, by pulling the tool control wire during operation of the surgical tool can induce straightening of the tip—a phenomenon known as crosstalk which is to be avoided.
• One particular application of a steerable tube is in the field of neurosurgery. Neurosurgical endoscopic intraventricular procedures are typically performed with a neurosurgical instrument known as the Caemaert endoscope. It is a long rigid shaft with an external diameter of ˜6 mm and four lumens. One lumen is for an optic element, one for a working channel, and two for rinsing fluid. The endoscope is introduced through a burr hole in the skull; the shaft intrudes the brain tissue at a non-eloquent area before entering the fluid filled ventricles. To reach the most central ventricle—known as the third ventricle—passage through an important ring-like structure, the foramen of Monroe, is necessary. Damage to this structure causes amnesia. Access to the third ventricle allows several surgical procedures to be performed such as perforating membranes or removing tumors. The latter is the most challenging procedure, requiring the sequential use of coagulation, grasping and aspiration. Using present technology, it is not possible to have more than one steerable tube inside the endoscopic shaft, especially when one of the tubes is a steerable aspiration catheter which also requires a large lumen compatible with removal of particles of tissue.
• The present invention, therefore, address the problems of the art by providing a steerable tube having a large diameter lumen while minimizing the outer diameter, which is reliable and cost-effective to manufacture.
SUMMARY OF THE INVENTION
• One embodiment of the invention is a steerable tube (100), comprising a hollow elongate tubular member (1) having a proximal end (2), distal end (3), a wall surface disposed between said proximal (2) and distal end (3), the wall having a substantially uniform thickness, a bend-resistive zone (6) flanked by a proximal bendable zone (4) that forms a controller and a distal bendable zone (5) that forms an effector, whereby
• • the wall of the tubular member (1) in the bend-resistive zone (6) comprises a structure that is a plurality of longitudinal slits (7), forming a plurality of longitudinal strips (8,8′),
  • the wall of the tubular member (1) in the proximal bendable zone (4) and the distal bendable zone (5) comprises a structure that is a plurality of longitudinal wires (9,9′,10,10′),
  • at least one strip (8) is in connection with a wire (9) in the proximal bendable zone (4) and a wire (10) in the distal bendable zone (5), such that translation by said wire (9) in the controller is transmitted via the strip (8) to said wire (10) in the effector,
  • a proximal annular region (11) of the tubular member (1), proximal to the proximal bendable zone (4) is circumferentially intact,
  • a distal annular region (12) of the tubular member (1) distal to the distal bendable zone (5) is circumferentially intact.
• Another embodiment of the invention is a steerable tube (100), comprising a hollow elongate tubular member (1) having a proximal end (2), distal end (3), a wall surface disposed between said proximal (2) and distal end (3), a bend-resistive zone (6) flanked by a proximal bendable zone (4) that forms a controller and a distal bendable zone (5) that forms an effector, whereby
• • the wall of the tubular member (1) in the bend-resistive zone (6) comprises a structure that is a plurality of longitudinal slits (7), forming a plurality of longitudinal strips (8,8′),
  • the wall of the tubular member (1) in the proximal bendable zone (4) and the distal bendable zone (5) comprises a structure that is a plurality of longitudinal wires (9,9′,10,10′),
  • at least one strip (8) is in connection with a wire (9) in the proximal bendable zone (4) and a wire (10) in the distal bendable zone (5), such that translation by said wire (9) in the controller is transmitted via the strip (8) to said wire (10) in the effector,
  • a proximal annular region (11) of the tubular member (1), proximal to the proximal bendable zone (4) to which the proximal wires (9) are anchored,
  • a distal annular region (12) of the tubular member (1) distal to the distal bendable zone (5) to which the distal wires (10) are anchored.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein one or more of the longitudinal strips (8,8′) is aligned or inclined to a longitudinal (A-A′) axis of the hollow elongate tubular member (1).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein one or more of the longitudinal strips (8,8′) is at least partly linear.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein one or more of the longitudinal strips (8,8′) is provided with interconnections, non-radial slits or spiral cuts to hold the strips together.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the plurality of longitudinal wires (9,9′,10,10′) are separated by longitudinal apertures (13,13′,14,14′) in the proximal bendable zone (4) and/or a distal bendable zone (5).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein a wire (9,9′,10,10′) in a bendable zone (4,5) is more narrow than a strip (8) in the bend-resistive zone (6).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the circumferential width of a wire (9,9′,10,10′) in the narrowest part, is between 50%, and 90% less than the circumferential width of a strip (8) in the narrowest part.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the circumferential width of a wire (9,9′,10,10′) in the narrowest part, is between 0%, and 90% less than the circumferential width of a strip (8) in the narrowest part.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein one or more of the wires (9,9′,10,10′) is aligned or inclined to a longitudinal (A-A′) axis of the hollow elongate tubular member (1).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein one or more of the wires (9,9′,10,10′) is at least partly linear.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the proximal bendable zone (4) and/or distal bendable zone (5) is substantially formed from a material different to that of the bend-resistive zone (6).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising an outer sheath (20), at least partly covering the outside surface of the hollow elongate tubular member (1) while permitting translational movements of the strips (8,8′) and wires (9,9′,10,10′) within.
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the outer sheath (20), is flexible in the region covering at least the bendable zones (4,5).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the outer sheath (20), is less flexible in the region covering the bend-resistive zone (6) compared with in the region covering at least the bendable zones (4,5).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising an inner lining (50) that at least partly lines the lumen (15) of the hollow elongate tubular member (1) while permitting translational movements of the strips (8,8′) and wires (9,9′,10,10′) outside.
• Another embodiment of the invention is a steerable tube (100) as described above, whereby one or more of the apertures (13,13′,14,14′) between the wires (9,9′,10,10′) is provided with a spacer (16).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising a handgripper (70) at the proximal end (2), configured to control a set of forceps (80) at the distal end (3).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising an endoscopic camera or lens at the distal end (3).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising a cutting tool (scissors, knife, drill, mill, grinder, knibbler) at the distal end (3).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising a sensor (temperature, moisture, light, gas, radioactivity) at the distal end (3).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising electrodes (stimulation, recording, coagulation) at the distal end (3).
• Another embodiment of the invention is a steerable tube (100) as described above, whereby the zones are formed from a substantially solid tube wall of the hollow tubular member during manufacture, and the bendable zones are formed by removing material from said substantially solid tube wall.
• Another embodiment of the invention is a steerable tube (100) as described above, whereby a wire (9) in the proximal bendable zone (4) and/or a wire (10) in the distal bendable zone (5) is disposed with one or more cuts configured to increase flexibility of said wire
• Another embodiment of the invention is a steerable tube (100) as described above, whereby the proximal annular region (11) and/or distal annular region (12) are formed from one or more circumferentially interlocking elements.
• Another embodiment of the invention is a steerable tube (100) as described above, whereby a wire (9) in the proximal bendable zone (4) and/or a wire (10) in the distal bendable zone (5) is connected to a strip by welding, gluing, soldering or by interlocking.
• Another embodiment of the invention is a steerable tube (100) as described above, whereby the thickness of a wire (9) in the proximal bendable zone (4) in its thinnest region and/or a wire (10) in the distal bendable zone (5) is less than that of a connecting strip (8) in its thinnest region.
• Another embodiment of the invention is a steerable tube (100) as described above, whereby a wire (9) in the proximal bendable zone (4) and/or a wire (10) in the distal bendable zone (5) is made from a more flexible material than use in a connecting strip (8).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the elongate tubular member (1) comprises a side port (40) formed from an aperture between two adjacent strips (8,8′).
• Another embodiment of the invention is a steerable tube (100) as described above, wherein the elongate tubular member (1) incorporates a limit stop mechanism (41) that limits the extent of relative slidable movement between two strips (8,8′).
• Another embodiment of the invention is a steerable tube (100) as described above, whereby elongate tubular member (1), and one of the outer sheath (20), or inner lining (50) are coaxially rotatable elements, further comprises a rotation limiting mechanism (44,44′) formed from a radial protrusion (45a,45′a) present in any one coaxially rotatable element, in longitudinal slidable connection with a reciprocating slot (45b,45′b) in another coaxially rotatable element of the steerable tube (100) configured to reduce or prevent revolute movement by the elongate tubular member (1) relative to the outer sheath (20) or inner lining (50).
• Another embodiment of the invention is a steerable tube (100) as described above, further comprising an electromechanical actuator configured to controllably move the proximal bendable zone (4) within its range of movement, and optionally to rotate the steerable tube (100) around its longitudinal (A-A′) axis.
• Another embodiment of the invention is a steerable tube (100) as described above, further a braking mechanism, configured, to prevent slidable movements by the strips (8,8′) relative to the outer sheath (20) or inner lining (50).
• Another embodiment of the invention is a steering guide (119—FIG. 17) comprising an elongated longitudinal member (122) having a proximal (126) and distal (128) end, the proximal end (126) disposed with a brace (123) for attachment to a part of a bodily arm, and the distal end (128) disposed with an endoport (160) configured for attachment to a medical instrument (120), said steering guide configured to place a proximal end (126) of the instrument in the vicinity of the hand (138) of said arm, and for pivotal movement of the instrument (120) actuated by movement said part of the arm.
• Another embodiment of the invention is a lockable articulated arm (170—FIG. 18) comprising a plurality of tandemly arranged, rigid links (172,174,176,178) connected by lockable joints (180,182,184) having at one end a base link (172) configured for rigid attachment to an operating table (171), and at the other end, an effector link (178) connected to a lockable ball and socket joint (152), the ball and socket joint configured for coupling to an endoport device (160), through which a medical instrument (120) is disposed, which lockable ball joint (152) is further configured to pivot the endoport device (160) relative to the effector link (178).
• Another embodiment of the invention is a rotation limiting mechanism for a steerable tube comprising a plurality of cables arranged in a cylinder, circumferentially flanked by an inner and outer tubular support whereby the cylindrically arranged cables, and one of the inner and outer tubular supports are coaxially rotatable elements, which rotation limiting mechanism is formed from a radial protrusion present in any one coaxially rotatable element, in longitudinal slidable connection with a reciprocating slot in another coaxially rotatable element of the steerable tube configured to reduce or prevent coaxially rotation by the cylindrically arranged cables relative to the inner or outer tubular support.
BRIEF DESCRIPTION OF THE FIGURES
• FIGS. 1A and 1B show cut away sections devices in the art comprising a plurality of cables fed through guide sleeves (FIG. 1A) or disposed side by side (FIG. 1B).
• FIGS. 1C and 1D show transverse sections across the devices of the art shown inFIGS. 1A and 1B respectively, together with indications of outer (OD) and inner (ID) tube diameters.
• FIG. 2A shows cut away section device of the present invention comprising an elongatetubular member1, disposed with both optionalouter sheath20 andinner tube50. The outer sheath and inner tube, explained below as not being essential, are shown to facilitate comparison with the prior art.
• FIG. 2B shows axial view section device of the present invention, together with indications of outer (OD) and inner (ID) tube diameters. A favorable comparison with the dimensions of devices known in the art is apparent.
• FIG. 3A depicts a perspective view of a steerable tube of the present invention in a non-bent state.
• FIG. 3B depicts a perspective view of a steerable tube of the present invention whereby the proximal and distal bendable zones are flexed.
• FIG. 4A illustrates the dimensions of a steerable tube of the present invention, andFIGS. 4B to 4D illustrates the dimensions of the transverse cross sections.
• FIG. 5 depicts a perspective view of the proximal bendable zone disposed with a spacer in the apertures.
• FIG. 6A to 6C depicts alternative configurations for a spacing means to stabilize the wires. InFIG. 6A, alternate wires are bent in an undulating form, inFIG. 6B, the wires are disposed with teeth, inFIG. 6C the wires is disposed with hollow rings.
• FIG. 7 depicts a perspective view of an outer sheath.
• FIGS. 8A to 8C depicts perspective views where the strips are provided with additional circumferential cuts (FIG. 8A), and examples of radial and non-radial slits (FIG. 8B) or an interconnection (FIG. 8C).
• FIG. 9A depicts a side port created by cutting of apertures between two adjacent strips to allow lateral exit of, for example, wires, electrical cables or aspiration ducts.
• FIG. 9B depicts a limit stop mechanism that controls the extent of slidable movement by two strips, which limits stop is formed from a tooth fixed to one strip in slidable connection with a reciprocating notch in an adjacent strip that limits, for instance, the angle of motion of the instrument.
• FIG. 10A. depicts an example of a rotation stop formed from a radial protrusion (a keel) fixed to the inner tube, in slidable connection with a reciprocating slot formed between two strips of the elongate tubular member, which rotation stop decreases the torsion of steerable tube around the central axis relative to the inner tube.
• FIG. 10B. depicts a further example of a rotation stop formed from a radial protrusion (keel) fixed to the inner tube, in slidable connection with a reciprocating slot formed from a remove strip of the elongate tubular member, which rotation stop decreases torsion of strips around the central axis relative to the inner tube.
• FIGS. 11A and 11B depict the keel ofFIGS. 10A and 10B in a detailed view.
• FIG. 12 illustrates a perspective view of the distal bendable zone, where four strips are provided with piezomotors.
• FIG. 13A illustrates a perspective view of coaxial steering tubes
• FIG. 13B depicts a sequence of tandemly arranged steerable tubes (motorized), forming a snake-like articulated tube having several degrees of freedom of movement.
• FIGS. 14A and 14B illustrate a steerable tube from the assembly of several parts to form an intact annular region for anchoring the wires.
• FIGS. 15A to 15D provide perspectives view of a steerable tube adapted with a gripper (FIGS. 15A and B) and forceps (FIGS. 15C and D).
• FIG. 16A illustrate a perspective view of the proximal bendable zone, where the strips are joined to rod-shaped wires, which wires are made from a different material (e.g. Nitinol) from the strips (e.g. made from stainless steel).
• FIG. 16B illustrate a perspective view of the proximal bendable zone, where the strips are joined to the wires by a joint, which wires are made from a different material from the strips.
• FIG. 17 shows a schematic view of a steering guide for supporting and pivotally moving an invasive medical instrument having a longitudinal axis, within a bodily cavity.
• FIG. 18 shows a schematic view of a lockable articulated arm of the invention.
• FIG. 19 shows a cross-sectional view of the ball and socket joint and endoport that forms part of the lockable articulated arm.
DETAILED DESCRIPTION OF THE INVENTION
• Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art. All publications referenced herein are incorporated by reference thereto. All United States patents and patent applications referenced herein are incorporated by reference herein in their entirety including the drawings.
• The articles “a” and “an” are used herein to refer to one or to more than one, i.e. to at least one of the grammatical object of the article. By way of example, “a linkage” means one linkage or more than one linkage.
• The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, a number of object, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0)
• The terms “distal” and “proximal” are used through the specification, and are terms generally understood in the field to mean towards (proximal) or away (distal) from the surgeon's side of the apparatus. Thus, “proximal” means towards the surgeon's side and, therefore, away from the patient's side. Conversely, “distal” means towards the patient's side and, therefore, away from the surgeon's side.
• Reference is made in the description below to the drawings which exemplify particular embodiments of the invention; they are not at all intended to be limiting. It will be understood that the skilled person may adapt the device and substitute components and features according to the common practices of the skilled artisan.
• The present invention relates to a steerable tube with thin-walls and having ends that can move in omni-directional manner and are mechanically coupled. With reference toFIGS. 3A and B an embodiment of the present invention concernssteerable tube100, comprising a hollow elongatetubular member1 having aproximal end2, adistal end3, a wall surface disposed between said proximal2 anddistal end3, a bend-resistive zone6 flanked by a proximal bendable zone4 that forms a controller and a distalbendable zone5 that forms an effector, whereby:
• • the wall of thetubular member1 in a bend-resistive zone6 comprises a structure that is a plurality oflongitudinal slits7, forming a plurality oflongitudinal strips8,8′,
  • the wall of thetubular member1 in a proximal bendable zone4 and a distalbendable zone5 comprises a structure that is a plurality oflongitudinal wires9,9′,10,10′,
  • at least onestrip8 is in connection with awire9 in the proximal bendable zone4 and awire10 in the distalbendable zone5, such that translation by saidwire9 in the controller is transmitted via thestrip8 to saidwire10 in the effector,
  • a proximalannular region11 of thetubular member1, proximal to the proximal bendable zone4,
  • a distalannular region12 of thetubular member11 distal to the distalbendable zone5.
• Another embodiment, of the present invention is a hollow elongatetubular member1 having aproximal end2 anddistal end3, comprising:
• • a wall surface disposed between said proximal2 anddistal end3,
  • a proximal bendable zone4 that forms a controller,
  • a distalbendable zone5 that forms an effector and flexes responsive to movements of the controller, and,
  • a bend-resistive zone6 between theaforementioned zones4,5 that transmits movements of the controller to the effector,
    whereby:
  • the wall of the tubular member in the bend-resistive zone6 comprises a structure that is a plurality oflongitudinal slits7, flanking a plurality oflongitudinal strips8,8′,
  • the wall of the tubular member in proximal bendable zone4 comprises a structure that is a plurality of longitudinalproximal wires9,9′,
  • the wall of the tubular member in distalbendable zone5 comprises a structure that is a plurality of longitudinaldistal wires10,10′,
  • at least onestrip8 is in connection with awire9 in the proximal bendable zone4 and awire10 in the distalbendable zone5, such that translation by saidwire9 in the controller is transmitted via thestrip8 to saidwire10 in the effector,
  • a proximalannular region11 of thetubular member1, is proximal to the proximal bendable zone4, and
  • a distalannular region12 of thetubular member11 is distal to the distalbendable zone5.
• The steering technology is formed in the wall of thetubular member1 itself, thereby reducing significantly the wall thickness, and obviating the requirement of cables and associated technical difficulties with connecting, aligning and pre-tensioning cables cables. Thesteerable tube100 is typically formed from a single, substantially solid-walled hollow elongatetubular member1 which may be cut according to the invention, preferably using an accurate cutting system. Affixation techniques are not essential, and thus bulky joints typically associated with conventional tubes may be avoided, and do not conflict with a narrow profile. The invention thus provides a streamlined continuation of steering strips to the ends of the tube, whereby the risk of breakage is significantly reduced. Sterilization is facilitated since the parts are dismountable.
• Alternatively the tubular member is formed by assembling one or more separately formed jig-sawed pieces.
Bendable Zones
• Abendable zone4,5 is a region in which the hollow elongatetubular member1 is able to flex i.e. diverge from a longitudinal axis (A-A′) of the bend-resistive zone6. Preferably, thetubular member1 is able to bend in any direction providing left, right, forward, backwards movements, and movements in between to the effector. The construction of the device may alternatively allow a restricted movement, for example, when a plurality ofwires9,9′,10,10′ is connected to thesame strip8 providing, for instance, only a left and right movement by thebendable zone4,5.
• According to one aspect of the invention, the wall of the tubular member in proximal bendable zone4 comprises a structure that is a plurality of longitudinalproximal wires9,9′ separated bylongitudinal apertures13,13′. In this instance, flexibility in thebendable zones4,5 is achieved in principal by thelongitudinal apertures13,13′,14,14′ in the wall of the elongatetubular member1 which are shaped to provide a plurality ofnarrow wires9,9′,10,10′. The apertures and hence wires are preferably evenly arranged around the circumference of the elongate tubular member, thereby forming a tubular wall that can bend without kinking. The number ofwires9,9′,10,10′ is preferably 1, 2, 3, 4, 5, 6, 7, 8 or more. The number ofapertures13,13′,14,14′ is preferably 2, 3, 4, 5, 6, 7, 8 or more.
• The skilled person will appreciate that thebendable zones4,5 may still have the requisite bending properties even whenlongitudinal apertures13,13′ are absent. In such case, awire9,9′,10,10′ will have the same circumferential width as astrip8 and may be an extension of astrip8. Typically anouter sheath20 will contribute to the differential flexibility in thebendable zones4,5 and bend resistive zone6 as explained elsewhere herein. Thewires9,9′,10,10′ are preferably evenly arranged around the circumference of the elongate tubular member, thereby forming a tubular wall. The number ofwires9,9′,10,10′ is preferably 1, 2, 3, 4, 5, 6, 7, 8 or more.
• Awire9,9′,10,10′ in abendable zone4,5 may be more narrow than astrip8 in the bend-resistive zone6, and consequently is able to adopt more flexibility which contributes to the bending property of the zones. Alternatively, awire9,9′,10,10′ in abendable zone4,5 may be the same width as astrip8 in the bend-resistive zone6 as explained herein. According to one aspect of the invention, the circumferential width of awire9,9′,10,10′ (WPW or WDW) in the narrowest part, is 0%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90% less than the circumferential width of astrip8, (WS) in the narrowest part, or a value in the range between any two of the aforementioned values. Preferably the value of WPW or WDW is between 50% and 80%, or between 0% and 80% less than the value of WS, though in practice the precise percentage will depend on the final diameter of the elongate tubular member and material used.
• According to one aspect of the invention, the steerable tube has one or more spacers configured to maintain distance between the wires. If awire9,9′,10,10′ is narrowed extensively, for example, when using only threestrips8, the use of a spacer16 (seeFIG. 5) in one or more of theapertures13,13′,14,14′ between thenarrow wires9,9′,10,10′ may provide smoother movements by reducing buckling of the wires, though it is not essential. It will be appreciated that a spacer may be curved to match the cylindrical curvature of the elongatetubular member1.
• Thespacer16 may be attached to theannular region11,12. Parts of the wall left behind during the laser-cutting can create these fixed spacers.
• Alternatively, spacing between the wires may be maintained by employing one or more spacers on awire9, in fixed attachment thereto, configured for slidable contact with anadjacent wire9′ thereby maintaining its distance therefrom.
• According to one aspect of the invention, the aforementioned wire-bound spacer is formed by one or more bends in thewire9. The wire so bent17,17′ may have a undulating shape as shown, for example inFIG. 6A. The undulations, having a concave (upper) and convex (lower) part, are in slidable contact with straight (non-bent)wires9,9′ adjacent on both sides. It is within the scope of the invention that the bent wire has a concave or convex undulation (not shown), and the undulation is in slidable contact with a straight region of an adjacent wire on one side.
• The number of undulations per wire, where present, may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more, depending on the size of the undulation and the length of the wire. For example, thebent wire17,17′ depicted inFIG. 6A is disposed with5 undulations.
• Alternatively or in addition, an aforementioned wire-bound spacer is formed from a tooth-shaped protrusion in fixed attachment to a wire, configured to slidably contact an adjacent wire. A tooth-shapedspacer18,18″, may be attached in either a concave or convex relation to the longitudinal length of the wire, and is in slidable contact a straight region of an adjacent wire on one side as shown, for example, inFIG. 6B. Alternatively, two or more tooth-shaped spacers may be attached one in a concave and another in a convex relation to the longitudinal length of the wire, and is in slidable contact a straight region of adjacent wires on both sides (not shown). Said adjacent wires may be straight, or may be disposed with one or more teeth. The number of tooth-shaped per wire, where present, may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more, depending on the size of the undulation and the length of the wire. For example, thewire9,9′ depicted inFIG. 6B is disposed with2 undulations.
• Alternatively or in addition, an aforementioned wire-bound spacer may be formed from the structure arising when the above-mentioned concave and convex undulations are superimposed at the same position on the wire, i.e. a ring-shaped spacer is formed that is in slidable contact with a straight region ofadjacent wires9,9′ on both sides. Said adjacent wires may be straight, or may be disposed with one or more ring-shaped spacers. Said ring shapedspacers19,19′ may be formed from a hollow ring as depicted inFIG. 6C, or from a solid ring (not shown). The ring may be circular or oval. The number of rings per wire, where present, may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more, depending on the size of the ring and the length of the wire. For example, thewire9,9′ depicted inFIG. 6C is disposed with1 undulation.
• It will be appreciated from the above that the invention includes any other cutting patterns to maintain spacing between the wires within its scope.
• It is an option that one or more of thewires9,9′,10,10′ in thebendable zones4,5 is thinned i.e. reduced in material thickness (TP or TD) to provide increased flexibility. Thinning may be achieved by chemical etching or other techniques known in the art. It is an option that one or more of thewires9,9′,10,10′ in thebendable zones4,5 is rounded to remove sharp corners. Rounding may be achieved by electropolishing or other techniques known in the art.
• Thewires9,9′,10,10′ that provide flexibility need not be linear and aligned with the longitudinal (A-A′) axis in an unflexed state as shown in theFIG. 4A, for example. One or more of thewires9,9′,10,10′ may be aligned with or inclined to the longitudinal (A-A′) axis of the hollow elongatetubular member1. One or more of thewires9,9′,10,10′ may be at least partly linear, though other patterns are envisaged, for example, wires that are undulating17 (FIG. 6A), or curved shaped. or any suitable pattern as seen, for instance, in stent production are all within the scope of the invention. As mentioned earlier, one or more wires may be disposed with tooth-shaped spacers18 (FIG. 6B), or disposed with ring-shaped spacers19 (FIG. 6C).
• According to one aspect of the invention, awire9 is asolid nitinol rod95,95′ inserted or laser welded in a small burr hole in thestrip8 and annular region11 (FIG. 16A). According to another aspect of the invention, awire9 is made from a different material to the adjoiningstrip8, and is attached to the strip by joint90 (FIG. 16B). The joint90 is preferably a dove-tail joint, or the like.
Controller
• When the controller (proximal bendable zone4) is flexed, its movements are transmitted via the bend-resistive zone6 to the effector (distal bendable zone5) which flexes responsive to movements of the controller. The controller may be manually manipulated or it can be coupled to mechanical movement means (e.g. electromechanical). In the latter case, the movements of the controller may be servomechanically actuated, for example, by use of a telesurgical system. Electromechanical movement may also alternatively or additionally be realised by the use of linear motors that operate on thestrips8 of thetubular member1 as described elsewhere herein.
• Increased bending-couple or leverage in the proximal bendable zone4 (controller) can be achieved by a progressive increase of thetubular member1 diameter towards theproximal end2 in comparison to the rest of the elongate tubular member. According to one aspect of the invention, the diameter of the tube in the proximal bendable zone4 is 5%, 10%, 15%, 20%, 25%, 30%, 50%, 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, 1000%, 2000% or more, greater than the diameter of the tube in the remainder of the tube when comparing the maximum diameter of the proximal bendable zone4 with the minimum diameter of the remainder of the tube, or a value in the range between any two of the aforementioned values.
• Alternatively the proximal end could be fixed to a gimbal-plate or gimbal-ball. This increased bending-couple might be of interested for the mostly long endovascular catheters in which more force-lost is seen due to torturous path of the tube in the vascular structures.
• As mentioned elsewhere, the proximal bendable zone4 (controller) may be coupled to a mechanical movement means, particularly to an electromechanical means. One embodiment of the invention, is an electromechanical controller for asteerable tube100 of the invention comprising a holder configured for dismountably attaching a steerable tube of the invention, and an electromechanical actuator configured to controllably move the proximal bendable zone4 (controller) within its range of movement, and optionally to rotate the steerable tube around its central axis. The holder preferably attaches in the region of the bend-resistive zone6. The attachment is dismountable, meaning that steerable tubes can be interchanged with the same controller; this has the advantage that a steerable tube may be removed for sterilization or replaced where necessary without need for changing the electromechanical controller. The electromechanical actuator may comprise two or more servo motors, arranged for two or three axis control around a pivotal point of the proximal bendable zone4. The skilled person will be able to implement suitable working configuration of the electromechanical controller based on the guidance herein.
Effector
• The effector (distal bendable zone5) moves responsive to movements of the controller, typically in mirrored manner. For example, a forward movement by the controller will result in a backward movement by the effector and vice versa.
• The effector of the invention provides an excellent steering stability as a result of several factors. A large bending moment is available since the wires terminate at a far lateral offset relative to the tube centerline. Further, both pulling and pushing are transmitted to the effector, which forces cooperate to provide both a large net mechanical force and exquisite control. The effector has a high bending stiffness to limit undesirable deflections such as S-shape bending and has a high torsional stiffness. The effector can withstand severe lateral loads and allows axial rotation (transmission of torque) even in a bent position. This is particularly of importance for example, if it is required to bring together the jaws of a scissor perpendicular to a blood vessel.
• The elongatetubular member1 of the invention is hollow, thus it may act as a lumen providing a passage from the proximal2 to the distal3 tip of the elongate tubular member. The effector, therefore, is provided with the lumen which can receive operating wires or fluids when the lumen is lined with a water impermeable substance. Furthermore, the effector may be adapted to support one or more additional instruments for remote operation such as clamps, graspers, scissors, staplers, aspiration catheter, laser fibers and needle holders. The adaptation of the effector will be readily understood by the skilled artisan, and is discussed further below.
Bend Resistive Zone
• The bend-resistive zone6 connects the proximal bendable zone4 with the distalbendable zone5 and transmits movements of the controller to the effector. The wall of the tubular member in the bend-resistive zone6 comprises a structure that is a plurality oflongitudinal slits7, that flank a plurality oflongitudinal strips8,8′. The slits cut across the bend-resistive zone6 in the longitudinal (A-A′) direction allowing each strip to slide independently of the adjacent strip. In transmitting forces, the strips exhibit negligible compliance and thus efficient use is made of almost the complete wall structure. It will be apparent that when the strips are aligned adjacently to form the hollow elongatetubular member1, the flexibility of the bend-resistive zone6 is reduced. The bend-resistive zone6 is considerably less flexible than thebendable zones4,5. The flexibility may be attributable, for example, to the presence of no or few apertures which would otherwise provide flexibility. Alternatively, the inner lining or outer sheath in the bend resistive zone may be less flexible than in the bendable zone. Thelongitudinal slits7 and hencelongitudinal strips8,8′ are preferably evenly arranged around the circumference of the elongate tubular member. The number oflongitudinal strips8,8′ is preferably 2, 3, 4, 5, 6, 7, 8 or more. The number oflongitudinal slits7 is preferably 2, 3, 4, 5, 6, 7, 8 or more.
• The degree of bendability in the bend-resistive zone6 while being less than that in thebendable zones4,5 will depend on the number oflongitudinal strips8,8′ or slits7, the material used to form the elongatetubular member1 and its thickness.
• As mentioned already, at least onestrip8 is in mechanical connection with awire9 in the proximal bendable zone4 and awire10 in the distalbendable zone5, such that translation by saidwire9 in the controller is transmitted via thestrip8 to saidwire10 in the effector. The connection is generally rigid. The number of wires connected to a single strip is typically two—oneproximal wire9,9′ and onedistal wire10,10′—however, it is not necessarily limited to this number. It is envisaged that more than two wires can be connect to asingle strip8 in order to provide, for example, a restricted movement which can be desirable in applications where the full range of motion might otherwise lead to damage to the object being inspected or operated on.
• As mentioned above, the circumferential width of awire9,9′,10,10′ (WPW or WDW) of a bendable zone, in the narrowest part, is 0%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90% less than the circumferential width of astrip8, (WS), of the bend-resistive zone6, in the narrowest part, or a value in the range between any two of the aforementioned values. Preferably the value of WPW or WDW is between 50 and 80%, or between 0 and 80% less than the value of WS, though in practice the precise percentage will depend on the final diameter of the elongate tubular member and material used.
• Thelongitudinal slits7 and hencelongitudinal strips8,8′ need not be linear and aligned with the longitudinal (A-A′) axis as shown in, for example,FIG. 4. One or more of thelongitudinal strips8,8′ may be aligned or inclined to a longitudinal (A-A′) axis of the hollow elongatetubular member1. One or more of thelongitudinal strips8,8′ may be at least partly linear, though other patterns are envisaged, for example, spiral strips, or any suitable pattern as seen, for instance, in stent production.
• According to one aspect of the invention, the bend resistive zone comprises a braking mechanism, configured, when activated to prevent slidable movements by thestrips8,8′. When the brake is applied, the position of the distalbendable zone5 is fixed; i.e. it becomes resistive to force applied thereto. The brake may take any form, for example, a compressible annular ring having an inner diameter that varies according to the degree of compression. The inner circumference of the ring applies pressure to thestrips8,8′ of the elongatetubular member1 when the ring is compressed along its central axis.
• According to one aspect of the invention, the elongatetubular member1 comprises aside port40 created by cutting an aperture between twoadjacent strips8,8′ as shown, for example, inFIG. 9A. The aperture is dimensioned to maintain integrity of the strip in the longitudinal direction. The width of the region of a strip that form said aperture may be less than the width, WS (FIG. 4C), of a strip. Theside port40 allows side access to a hollow of thesteerable tube100 orinner lining50. Theside port40 may allow exit of wires, electrical cables or aspiration ducts from a hollow of the elongatetubular member1 orinner lining50. Alternatively or in addition,side port40 may be in fluid connection with the distal3 tip of thesteerable tube100, allowing the introduction of liquids (e.g. medicaments, washing solutions, contrast agents) and/or aspiration in the vicinity of the distal3 tip. The skilled artisan will appreciate that anyinner lining50 orouter sheath20 will be disposed with a corresponding aperture, aligned with the aperture formed in the elongatetubular member1.
• According to one aspect of the invention, the elongatetubular member1 incorporates alimit stop mechanism41 that controls the extent of relative slidable movement between twostrips8,8′. In a preferred embodiment, depicted inFIG. 9B, thelimit stop41 is formed from atooth42afixed to the edge of onestrip8 in slidable connection with a reciprocating notch orcrenellation42bin an edge of anadjacent strip8′. Movement of thetooth42awithin thenotch42bis limited when thetooth42acontacts the distal orproximal notch42bedges at the extreme ranges of movement. Thelimit stop mechanism41 is preferably located within the bend resistive zone6. The effect of the limit stop is to restrict, for instance, the extent to which the instrument flexes i.e. the maximum angle of flexure.
• According to one aspect of the invention, thesteerable tube100 further comprises arotation limiting mechanism44,44′ (FIGS. 10A and B) formed from a radial protrusion (known as a keel herein)45a,45′apresent in one coaxially rotatable element (e.g. the elongate tubular member1) in longitudinal slidable connection with areciprocating slot45b,45′bin another coaxially rotatable element (e.gouter sheath20 or inner lining50) of thesteerable tube100 configured to reduce or prevent unwarranted revolute movement by the elongatetubular member1 relative to theouter sheath20 orinner lining50. While in the above example thekeel45a,45′ais present in the elongatetubular member1 and the slot is present in theouter sheath20 orinner lining50, it is within the scope of the invention that a slot may be present on the elongatetubular member1 and the keel present on theouter sheath20 orinner lining50. Therotation limiting mechanism44,44′ is preferably located within the bend resistive zone6. Therotation limiting mechanism44,44′ is of importance when lateral forces are applied to the tip of the instrument in a bent position, which would otherwise cause the tip to move and lose its placement.
• Theslot45b,45′bmay be any shape, depending on the desired movement at thedistal end3, though it should be narrow and engage with thekeel45a,45′asufficiently prevent free rotation of the distalbendable zone5 upon the application of a torque thereto. Preferably, theslot45b,45′bis straight and parallel with the longitudinal axis (A-A′) of the bend-resistive zone. According to one aspect of the invention a slot is formed along at least part of the length of astrip8,8′. According to another aspect of the invention a slot is formed along at least part of the length between of twoadjacent strips8,8′. According to another aspect of the invention a slot is formed form a strip of the elongatetubular member1 disconnected from the wires or annular regions as shown inFIG. 10B.
• Should a rotation movement be desired at the distalbendable zone5, the slot may be spiral. The spiral may permit an anti-clockwise or clockwise rotation simultaneous with flexure of the distalbendable zone5. The keel may be, but not necessarily, considerably shorter than the length of a strip.FIGS. 10A and 10B depicts asteerable tube100 disposed with arotation limiter44,44′ in which thekeel45a,45′ais disposed on theinner lining50 and theslot45b,45′bis disposed on the elongatetubular member1.FIGS. 11A and 11B show in detail thekeel45aof theinner lining50 disposed within the elongatetubular member1 depicted inFIGS. 10A and 10B respectively. Preferably there are 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more keel and slot pairs along the same linear path, depending on the length of the keel and of thesteerable tube1. Preferably there is at least one keel every 20, 30, 45, 60, 72, 90, 120, or 180 degrees.
• It is within the scope of the invention that the above-mentionedrotation limiter44,44′ is applied to any device, operating along similar principles, whereby forces are transmitted by a transmission means (e.g. strips, rods or cables) covered with an independently-rotatable inner or outer lining. For example, one or more cables ofFIG. 1D may be disposed with a keel that is in longitudinal slidable connection with a reciprocating slot in an outer sheath or inner lining of the steerable tube, which arrangement is configured to reduce or prevent unwarranted revolute movement by the cylinder of cables. One embodiment of the invention is rotation limiting mechanism for a steerable tube comprising a plurality of cables arranged in a hollow cylinder, circumferentially flanked by an inner and/or outer tubular support whereby the cylindrically arranged cables, and one of the inner and outer tubular supports are coaxially rotatable elements, which rotation limiting mechanism is formed from a radial protrusion present in any one coaxially rotatable element, in longitudinal slidable connection with a reciprocating slot in another coaxially rotatable element of the steerable tube configured to reduce or prevent co-axial rotation by the cylindrically arranged cables relative to the inner or outer tubular support.
• According to one aspect of the invention, the controller may operated by the use of linear motors such as piezomotors (e.g. Piezo LEGS®).Such piezomotors60 may be arranged radially around the strips (inside or outside, parallel or sequential) of the tubular member1 (FIG. 8).Piezomotors60 may be arranged around the inside or outside of the tubular member1 (FIG. 8). There may be one or more (e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) piezomotors60 perstrip8. The movement part of apiezomotor60 is in mechanical contact with astrip8, while a frame of thepiezomotor60 may be attached to a static element on the steerable tube, such as an outer sheath20 (not shown). According to one aspect of the invention, the strips may be actuated using Flexinol®. Flexinol® actuators contract, in a similar manner to muscles, by a shortening or elongation of approximately 4-5%; thus they contract when they are “on” and relax when they are “off”. Movement of the strips may be achieved by arranging insulating strips placed between the actuating strips8 of thehollow member1. Advantageously, the use of linear motors allow a plurality of motorized steerable tubes to be connected, end to end, that offers a snake like tube (FIG. 13B) having a wide range of motion at the effector end. It is not essential that the proximal bendable zone4 is present in such a configuration. When thesteerable tubes100 are joined by motorized revolute joints, the range of motion is further enhanced. One embodiment of the invention is a composite steerable tube formed from two or more (e.g. 2, 3, 4, 5, 6, 7, 8, 10 or more) motorised steerable tubes tandemly arranged, and connected by rigid or revolute joints. One embodiment of the invention is a composite steerable tube formed from two or more (e.g. 2, 3, 4, 5, 6, 7, 8, 10 or more) motorised steerable tubes devoid of the proximal bendable zone4 and proximalannular region11 tandemly arranged, and connected by rigid or revolute joints.
• Using a more complex cutting pattern, strips8,8′ are within the scope of the invention whereby one or more of thelongitudinal strips8,8′ are held together (interlocked) using interconnections (FIG. 8C), non-longitudinal slits (FIG. 8A), non-radial slits (FIG. 8B) or longitudinal spiral cuts. In this constellation, the inner and outer coverings may be, but not necessarily, omitted. In this way, issues of sterilization, concerning access of steam to all areas and tubes, can be circumvented. It is noted that another way to overcome problems with sterilization is to make the steerable tube and any covering or lining perforated and/or dismountable.
• Where a non-radial slit is employed (FIG. 8B), the slit diverges from the radius of the elongate tubular member.FIG. 8B depict the profile of slits taken in transverse (C-C′) cross-section across the bend-resistive zone. It is noted, the distance between respective strips is exaggerated; in practice the strips are in sliding contact. Normally, theslit7,7′ converges with the radius. When non-radial slits are used, the slits7-1,7-2 flanking a strip8-1 may both diverge from the radius producing strips8-1 with conical edges pointed outwards. Alternatively, when non-radial slits are used, the slits7-3,7-4 flanking a strip8-2 may both diverge from the radius producing strips8-2 with conical edges pointed inwards.
Annular Regions
• Proximal to the proximal bendable zone4 is a proximalannular region11 of the hollow elongatetubular member1. The proximalannular region11 is adjacent and proximal to the proximal bendable zone4. Theproximal wires9,9′ may be anchored to the proximalannular region11. The proximal annular region may be circumferentially intact. In other words an intact region of the hollow elongatetubular member1 may be uncut, having no slits or apertures, that would permit slidable movement within the proximalannular region11. According to another aspect of the invention, the proximalannular region11 is composed of one interlocking part that folds cylindrically to form a region of fixed circumferential shape. According to another aspect of the invention, the proximalannular region11 is composed of two or more interlocking subparts46,46′ (FIG. 14) that fits together cylindrically to form a region of fixed circumferential shape. The interlocking arrangement prevents relative slidable movement between the subparts. By virtue of this property the distalannular region12 may have a constant width; the width does not substantially change when the proximal bendable zone4 is flexed. The region may be ring-shaped.Wires9,9′ extending from the proximal bendable zone4 are rigidly attached to the proximalannular region11. Typically thewires9,9′ are evenly disposed around the circumference of the proximalannular region11.
• Similarly, distal to the distalbendable zone5 is a distalannular region12 of the hollow elongatetubular member1. The distalannular region12 is adjacent and distal to the distalbendable zone5. Thedistal wires10,10′ may be anchored to the distalannular region12. The distal annular region may be circumferentially intact. In other words an intact region of the hollow elongatetubular member1 may be uncut, having no slits or apertures that would permit slidable movement within the distalannular region12. According to one aspect of the invention, the distalannular region12 is composed of one interlocking part that folds cylindrically to form a region of fixed circumferential shape. According to another aspect of the invention, the distalannular region12 is composed of two or more interlocking subparts (FIG. 14) that fit together cylindrically to form a region of fixed circumferential shape. The interlocking arrangement prevents relative slidable movement between the subparts. By virtue of this property, the distalannular region12 may have a constant width; the width does not substantially change when the distalbendable zone5 is flexed. The region may be ring-shaped.Wires10,10′ extending from the distalbendable zone5 are rigidly attached to the distalannular region12. Typically thewires10,10′ are evenly disposed around the circumference of the distalannular region12.
• The use of one or more interlocking parts to form the distal12 and proximal11 annular region allow an efficient construction of the elongate tubular member from one, two or more cut or molded parts (FIG. 14) i.e. without the requirement for cutting an intact tube. For example, the elongate tubular member may be formed from a flat sheet of material, having the appropriate elements, folded cylindrically and joined at the ends by virtue of interlocking circumferential joints in the distal12 and proximal11 annular regions to form a working elongate tubular member. Alternatively, the separate strips, wires and annular regions segments, optionally thinned at the bendable zones, can be assembled by virtue of interlocking circumferential joints in the distal12 and proximal11 annular regions.
• Theannular region11,12 can be of any longitudinal length depending on the application. It should be of sufficient length, however, to provide enough strength that avoids distortion of theannular region11,12 by tensional forces in thewires9,9′,10,10′. Advantageously, it can be extended at theproximal end2 in order to provide a greater leverage. Alternatively, it may be extended at thedistal end2 in order to provide a greater movement. Shorter distalannular region12 will allow for a more precise angular control.
Materials of the Elongate Tubular Member
• The elongatetubular member1 can be made from any material which provides the requisite tensile and flexural properties. Suitable materials include stainless steel, cobalt-chromium, shape memory alloy such as Nitinol®, plastic, polymer, composites or other cutable material. According to one aspect of the invention, the elongatetubular member1 is made from the same material throughout, e.g. stainless steel or nitinol. According to one aspect of the invention, the elongatetubular member1 is made from two or more different materials, for instance one material (e.g. stainless steel) in the bend-resisitive zone6 and another material (e.g. nitinol) in thebendable zones4,5. An example of such configuration is given inFIGS. 16A and 16B and described elsewhere herein. Alternatively different materials within the same tube can be used e.g. extrusion with two different materials.
Shape and Dimensions of the Elongate Tubular Member
• The elongatetubular member1 preferably has a cylindrical shape in the non-flexed stated, having a longitudinal axis A-A′ (FIG. 4A). The dimensions discussed below refer to the elongatetubular member1 in the non-flexed state, and refer to a measurement at a maximum point and not to an average.
• The total length of the elongatetubular member1, L, from the tip of theproximal end2 to the tip of thedistal end3 will depend on the materials used in the elongate tubular member, considering its stretching and pushability properties, thickness and diameter. Theoretically, any length of elongate tubular member is possible providing sufficient leverage is provide by the proximal bendable zone, for example, by extending the length of the proximal annular region. In medical applications, a total length of up to 150 cm would be desirable (e.g. endovascular catheters) for, and it is envisaged for most applications needing fine control (e.g. surgery and endoscopes) that the total length will be between 10 cm and 40 cm.
• The length of the proximal bendable zone LP will depend on the materials used in the elongate tubular member as mentioned above, and also the degree of movement, force and accuracy needed. In general, the higher the value of LP, the greater the force transmitted to the effector, though larger movements would be required. Values of LP are expect to be 1%, 1.25, 2%, 2.5%, 3%, 3.5%, 4, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% the value of L. It is envisaged for most applications needing fine control that LP will be 0.5, 2 or 3 cm, preferably between 0.5 cm and 3 cm for a 40 cm elongatetubular member1.
• The length of the distal bendable zone LD will depend on the materials used in the elongate tubular member as mentioned above, and also the degree of movement, force and accuracy needed. In general, the higher the value of LD, the lower the force the end can apply, though the larger the movements. Values of LD are expect to be 1%, 1.25, 2%, 2.5%, 3%, 3.5%, 4, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% the value of L. It is envisaged for most applications needing fine control that LD will be 0.5, 2 or 3 cm, preferably between 0.5 cm and 3 cm for a 40 cm elongatetubular member1.
• The length of the proximal annular region LPR will depend on the materials used in the elongate tubular member as mentioned above, and the tensile (pulling) and compression (pushing) forces that the wires apply so as not to distort the proximal annular region. In general, the higher the value of LPR, the better the strength of the proximal annular region. In addition, a higher value of LPR will provide more leverage and hence more force to the effect. Values of LPR are expect to be 0.25, 0.5%, 0.625% 0.75%, 1%, 1.25, 2%, 2.5%, 3%, 3.5%, 4, 4.5%, 5%, 10% the value of L. It is envisaged for most applications where the proximal annular region will provide support and have no additional leverage that LDR will be between 0.5 cm and 5 cm for a 40 cm elongatetubular member1.
• The length of the distal annular region LDR will depend on the materials used in the elongate tubular member as mentioned above, and the tensile (pulling) and compression (pushing) forces that the wires apply so as not to distort the distal annular region. In general, the smaller the value of LDR, the better flexibility of the proximal annular region. Values of LDR are expect to be 0.25, 0.5%, 0.625% 0.75%, 1%, 1.25, 2%, 2.5%, 3%, 3.5%, 4, 4.5%, 5%, 10% the value of L. It is envisaged for most applications where the distal annular region will provide support LDR will be between 0.5 cm and 1 cm for a 40 cm elongatetubular member1.
• The internal diameter of the bend-resistive zone IDS is at the option of the user, in accordance with the size of cables or other elements that need to pass through the lumen. For surgical applications, a value of IDS between 1 mm to 8 mm, and 0.5 mm to 3 mm for endovascular application will cover most applications where fine control is necessary through a restrictive opening. Larger internal diameters are possible, for example, where mechanical structures are investigated and the size of the opening is not critical. The internal diameters of the proximal and distal bendable zones—IDP and IDD respectively—may be the same as the IDS. As mentioned previously, the diameter of the proximal bendable zones may gradually increase towards the proximal end in order to increase the bending couple i.e. leverage. According to one aspect of the invention, IDP may be 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, 1000%, 2000% or more, greater than IDS or IDD at its widest point, or a value in the range between any two of the aforementioned values.
• The external diameter of the bend-resistive zone ODS will be governed by the size of the internal diameter, and the opening available. For surgical application, a value of ODS between 1 mm to 8 mm will cover most applications where fine control is necessary through a restrictive opening. Larger external diameters are possible, for example, where mechanical structures are investigated and the size of the opening is not critical. The external diameters of the proximal and distal bendable zones—ODP and ODD respectively—may be the same as the ODS. As mentioned previously, the diameter of the proximal bendable zones may gradually increase towards the proximal end in order to improve flexibility. According to one aspect of the invention, ODP may be 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, 1000%, 2000% greater than ODS or ODD at its widest point, or a value in the range between any two of the aforementioned values.
• The thickness of the wall of the elongatetubular member1 is generally the same throughout, i.e. values of TP (thickness of the wire in the proximal bendable zone), TS (thickness of the strip in the bend-resistive zone), and TD (thickness of the wire in the distal bendable zone), will be similar. The wall may have a substantially uniform thickness. For most applications, the inner diameter needs to be maximized compared with the external diameter. However, in certain application, the walls may be thick relative to the inner diameter, leaving a small inner lumen, for example, just for a control cable. The thickness of the wall may be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 6 mm, preferably between 0.1 to 0.6 mm, though the skilled person will appreciate it will vary according to the material properties. As mentioned earlier, the wall can be thinned in either or both bendable zones, typically by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.
• The dimensions mentioned herein are provided strictly for guidance. The skilled person would appreciate that the dimensions of the elongate tubular member can be adapted within the teachings of the present invention and thus other dimensions are likewise feasible within the scope of the present invention.
Manufacture of the Tube
• The transmission and bending properties of the elongate tubular member may be provided by the pattern of cuts e.g. longitudinal cuts in the bend-resistive zone6 (transmission). Additional flexibility may be provided by cut-out apertures in thebendable zones4,5. A standard technique for the construction of a elongate tubular member of the present invention is laser cutting technology (FIG. 3A) which can produce the instrument in an automatic manner e.g. by computer numeric controlled (CNC) cutting. Adjustments to the cutting due to different lengths or diameters oftubular member1 can be automatically computed and modified cutting regimes implement. Other methods may also be suitable, including water jet cutting, electrochemical etching, electrical discharge machining, diamond cutting, simple knife cutting, or any other suitable technique preferably followed by a suitable surface treatment, like etching or electro-polishing to deburr and or round off possible sharp edges.
• As described elsewhere in the elongate tubular member may be formed from a flat sheet of material, appropriate cut, molded or stamped, that is bent cylindrically and joined at the mutual adjacent edges by virtue of interlocking circumferential joints in the distal12 and proximal11 annular regions to form a working elongate tubular member.
• It is within the scope of the invention that eachstrip8 of the elongatetubular member1 is formed individually. Formation might be achieved using any number of techniques, for example, by a molding or stamping process. Molding processes are well known in the art; typically, a polymer in the liquid state is injected into a mold corresponding to the desired shape, in which the polymer hardens. The hardened product may be subjected to a suitable surface treatment, such as polishing to deburr and or round off possible sharp edges. Stamping techniques are well understood in the art; typically a cutting stamp, having an outline shape corresponding to the desired product shape is applied to a sheet of material such as polymer or metal. The product so formed may be curved by passing through rollers or by molding over a curved surface. The plurality ofstrips8 so formed is used to assemble the elongatetubular member1. It will be appreciated that the above techniques may be applied to form segments of the elongatetubular member1. A segment comprises astrip8, attachedwires9,10 and a segment of the proximal11 and distal12 annular regions disposed with interlocking cut-outs or interconnections (e.g. dove-tail joints or the like) holding adjacent segments of the annular regions together circumferentially. In particular, the elongatetubular member1 depicted inFIG. 14A may be formed in this manner.
• Where the elongatetubular member1 is formed from two or more different materials, for example, the bend-resistive zone6 made from stainless steel and thebendable zones4,5 made from nitinol, said materials may be joined, for instance, by welding or gluing together intact tubes prior to cutting, and then cutting the compound tube so formed. Alternatively, separate tubes formed from the different materials may be cut according to the invention that are later joined using joints created by the cutting process as seen, for example,FIG. 16B. Alternatively, separate elements of the elongate tubular member (e.g. strips8,wires9,10, proximal and distalannular regions11,12) may be formed separately, and joined, for example, by welding, gluing or soldering.
Outer Sheath
• An outer sheath20 (FIGS. 2A and B,FIG. 7) may be present in a steerable tube of the invention, whichouter sheath20 at least partly covers the outside surface of the hollow elongatetubular member1. Preferably, theouter sheath20 covers at least the bend-resistive zones6 and thebendable zones4,5. Theouter sheath20 protects the hollow elongatetubular member1 from dirt and obstruction while permitting translational movements of thestrips8,8′ andwires9,9′,10,10′ within. In this regard, the outer surfaces of thestrips8,8′ andwires9,9′,10,10′ may be coated with a lubricating substance, such a Teflon or silicone. In addition, the surfaces (e.g. outer and/or inner) of theouter sheath20 may also be coated with a lubricating substance, such a Teflon or silicone. The outer sheath may play a constraining role to prevent thestrips8,8′ andwires9,9′,10,10′ from bending outwards. Therefore, the outer sheath will have the necessary tensile properties, showing no or little elastic behaviour in order to constrain radial forces of thestrips8,8′ andwires9,9′,10,10′. Theouter sheath20 may be liquid or gas impermeable. Theouter sheath20 is preferably thin-walled, and constructed to exhibit flexibility in thebendable zones4,5. It is preferably cylindrical.
• In a preferred aspect of the invention, and with reference toFIG. 7 theouter sheath20 is made of ahollow tube21 having aproximal end22,distal end23, a wall surface disposed between said proximal22 anddistal end23, the wall having a substantially uniform thickness, a flex-resistive region26 flanked by proximal24 and distal25 flexible regions, whereby the internal diameter of thehollow tube21 is greater than the external diameter of the elongatetubular member1. Thehollow tube21 is preferably placed over thetubular member1 and co-axially aligned therewith so that the flex-resistive region26 covers the bend-resistive zone6, the proximal24 and distal flexible regions cover the proximal4 and distal5 bendable zones of the elongatetubular member1 respectively.
• The wall of thehollow tube21 in the flex-resistive region26 is essentially intact, preferably being devoid of slits or apertures. The flex-resistive region26 is less flexible than theflexible regions24 of the outer sheath. The wall of thehollow tube21 in the proximalflexible region24 and the distal flexible region may comprise a structure that is a plurality oflinkages28 separated by strain-relief apertures29, whichlinkages28 andapertures29 allow the second tubular member to flex. Two or more separate series ofsuch apertures29 may be formed adjacent one another on opposite or different sides as shown inFIG. 7 of the tubular body to permit deflection or bending of the tubular body in multiple directions about its longitudinal axis (F-F′). Other known techniques that make rigid tubes more flexible are the use of spiral cuts, hinges cuts, dove-tail cuts, and heart-like cuts. The apertures and patterns can be cut using the methods mentioned herein, in particular laser cutting technology. To better control the bending radius, for instance less bending in the distal portion of the proximal bending zone, the apertures (or linkages) may have different sizes. Thehollow tube21 can be made from any biocompatible material which provides the requisite elastic and flexural properties. Suitable materials include stainless steel, cobalt-chromium, shape memory alloy such as Nitinol®, plastic, polymer, composites or other curable material.
• FIG. 7 depicts a perspective view of an instance of anouter sheath20. Shown is the wall of thesheath21 in the flex-resistive region26 devoid of apertures. The essentially continual wall structure reduces the flexibility of the flex-resistive region26.
• It is within the scope of the invention, that theouter sheath20 is formed from a tube that has inherent flexible properties, for example being made from material such as PTFE, polypropylene, or other silicone or rubberised polymeric substances which exhibits flexibility in the proximal bendable zone4 and the distalbendable zone5 when the outer sheath co-axially covers the elongatetubular member1. The region covering the bend resistive zone6 may be reinforced with to resist radial expansion or increase torsional stiffness, for example, using braiding. To prevent penetration of substances through the strain-relief apertures. an additional liquid impermeable cover (PTFE, silicone, heat shrink wrapper) may be utilised.
• According to one aspect of the invention, theouter sheath20 incorporates a braking mechanism, configured, when activated to prevent slidable movements by thestrips8,8′ of the elongatetubular member1. When the brake is applied, the position of the distalbendable zone5 is fixed; i.e. it becomes resistive to force applied thereto. The brake may take any form, for example, a compressible annular ring having an inner diameter that varies according to the degree of compression. The inner circumference of the ring applies pressure to thestrips8,8′ of the elongatetubular member1 when the ring is compressed along its central axis.
• As already mentioned above, the outer sheath can be omitted by observing a more complex cutting pattern; thestrips8,8′ are envisaged which are held together (interlocked) using interconnections (FIG. 8C), non-longitudinal slits (FIG. 8A), non-radial slits (FIG. 8B) or longitudinal spiral cuts. In this constellation, the inner and outer coverings may be, but not necessarily, omitted. In this way, issues of sterilization, concerning access of steam or plasma to all areas and tubes, can be circumvented.
Inner Lining
• An inner lining50 (FIGS. 2A and B) may be present that at least partly lines thelumen15 of the hollow elongatetubular member1. Theinner lining50 protects the inside hollow elongatetubular member1 from dirt and obstruction while permitting translational movements of thestrips8,8′ andwires9,9′,10,10′ outside. In this regard, the inner surfaces of thestrips8,8′ andwires9,9′,10,10′ may be coated with a lubricating substance, such a Teflon or silicone. In addition, the surfaces (e.g. outer and/or inner) of theinner lining50 may also be coated with a lubricating substance, such a Teflon or silicone. The inner lining may play a constraining role to prevent thestrips8,8′ andwires9,9′,10,10′ from bending inwards. Therefore, the inner lining will have the necessary compression properties, showing no or little elastic behaviour in order to constrain radial forces of thestrips8,8′ andwires9,9′,10,10′. Theinner lining50 may be liquid or gas impermeable. Theinner lining50 is preferably thin-walled, and constructed to exhibit flexibility in thebendable zones4,5. It is preferably cylindrical.
• Preferably, theinner lining50 is formed from a tube that has inherent flexible properties, employing a material such as PTFE, polypropylene, or other silicone or rubberised polymeric substances. Theinner lining50 may be formed from an inherently inflexible tube, made flexible by the addition of apertures cut from the tube walls and as described elsewhere herein. Preferably, the hollow tube is flexible over its whole length.
• The use of aninner lining50 is not essential. Thelumen15 of the hollow elongatetubular member1 can be obturated for example with a laser fiber, control cable for grasping forceps or scissors, aspiration catheter, bundle of glass fibers, power or data cables, a flexible rod with a lumen for electrical wires.
• According to one aspect of the invention, theinner lining50 is made of a hollow tube having a proximal end, distal end, a wall surface disposed between said proximal and distal end, the wall having a substantially uniform thickness, a flex-resisitive zone flanked by proximal and distal flexible region, whereby the external diameter of the hollow tube is less than the internal diameter of thetubular member1. The hollow tube is preferably placed within thetubular member1 and co-axially aligned therewith so that the flex-resisitive region covers the bend-resistive zone, the proximal and distal bendable zones cover the proximal4 and distal5 and flexible regions respectively.FIG. 2B depicts aninner lining50 within the proximal bendable zone4, having walls containing apertures and linkages, similar to thehollow tube21 that forms theouter sheath20. The embodiments above and which describeFIG. 5 of theouter sheath20 may be readily adapted to prepare an inner lining with the above mentioned properties.
• Additionally coaxial steering tubes can allow indifferent flexion on different parts of the complete tubeFIG. 13A. This could allow surgeons to go through one incision with two or more instruments. After entering the abdomen a first joint brings the instrument lateral while a second allows coming back medially towards the operative field. This concept allows performing the operation through one incision while maintaining an on-obstructed view on the operative field.
Adaptations
• As mentioned earlier, the proximal or distal ends of the instrument may be adapted with particular tools or components which may be attached to the tubular member, and/or to the optional outer sheath and/or to the optional inner lining. According to one example, theproximal end2 may be adapted with ahandgripper70 which controls a set offorceps80 at thedistal end3, which forceps80 are controlled by acontrol cable75 passing through the lumen, connected to the handgripper70 (FIGS. 15A to 15D). Thehandgripper70 may be formed from an essentially solid-walled thin tube, cut according to the techniques described herein. Such handgripper is shown inFIGS. 15A and 15B. The two handles71,72 of thegripper70 are formed by a pair of longitudinal cuts, and one hinge handle72 is created by a circumferential cut which creates tworevolute joints76 at the corners of the onehinge handle72. Supporting struts73 for thecontrol cable75 may be cut from thehandles71,72. Alternatively, instead of supporting struts an additional laser cut ring-like structure that becomes oval when compressing the handles may be employed. In this way, hinged movement by thehandle72 is converted to a linear movement by thewire75.
• Similarly, theforceps80 may be formed from an essentially solid-walled thin tube, cut according to the techniques describe herein.Such forceps80 is shown inFIGS. 15C and 15D. The twojaws81,82 of theforceps80 are formed by a pair of longitudinal cuts, and one hinge handle72 is created by a circumferential cut which creates tworevolute joints76 at the corners of the onehinge handle72. A supporting strut83 for thecontrol cable75 may be cut from the twojaws81,82. In this way, a linear movement by thecontrol cable75 is converted to a hinged movement by thejaw82.
• According to one embodiment of the invention, thestrips8,8′ of the hollow elongatetubular member1 are made from one material, while thewires9,9′ are made from another material. The wires and strips8,8′ are joined by interconnecting joints (FIG. 16A). Such hybrid structure might be of use to reduce the costs when expensive material are employed such as Nitinol; in such case, Nitinol may be used to form thewires9,9′ andannular regions11,12, while a cheaper alloys used to form thestrips8. Alternatively the wire could be replaced by small Nitinol rods inserted in the annular region and strips (FIG. 16B).
• For difficult-to-see and/or hard-to-reach places, thedistal end3 may advantageously by provided with an endoscopic camera or lens, which may be implemented by fiber scope or chip-on-a-stick.
• According to one aspect of the invention, thesteerable tube100 further comprises a cutting tool at thedistal end3. The cutting tool can be any, including but not limited to scissors, knife, drill, mill, grinder, saw, or knibbler.
• According to another aspect of the invention, thesteerable tube100 further comprises a sensor at thedistal end3. The sensor is preferably electronic, and concerts the detected phenomenon into electrical signals. The sensor can be any, including, but not limited to temperature, moisture, light (wavelength and/or intensity), gas, radioactivity, acoustic, and pressure.
• According to one aspect of the invention, thesteerable tube100 further comprising one or more electrodes at thedistal end3. The electrode can be any, including, but not limited to stimulation, recording, coagulation, reference.
• Another embodiment of the invention is an endoscope disposed with a plurality of lumens, whereby at least one lumen (for example, 1, 2, 3 or more) is provided with a steerable tube of the present invention. It is noted that the narrow profile of the steerable tubes allows the construction of an endoscope of standard diameter (e.g. 6.2 mm) comprising two steerable tubes, one in each lumen. Exceptionally, the presence of two steerable tubes permits co-operation at the tip, exemplified with one tube being disposed with a remote-controlled jaw to grasp an object and another tube disposed with a remote-controlled cutter, to sever the object. This level of control and co-operation between instruments has never before been achieved through narrow tube endoscopes. Further, the wide internal diameter of the steerable tube facilitates its role in aspiration such that excised tissue can be removed through the steerable tube without blockage. It is envisaged that, particularly in bodily-invasive procedures, the invention permits safer and more rapid manipulations while reducing the risk of infections.
Steering Guide
• Another embodiment of the invention is asteering guide119, exemplified inFIG. 17, configured for attachment to a part of the bodily arm of the user and which supports, through an attached endoport device160 (described further below), an invasivemedical instrument120 disposed with a longitudinal axis, including, but not necessarily limited to thesteerable tube100 of the present invention, permitting pivotal movement of theinstrument120, said pivotal movement actuated by said part of the arm. The pivotal movement referred to herein is the movement within a conical space around the point of a cone centered on a fulcrum point. Thus, the pivotal movement of theendoport device160 attached to the steering guide is around afulcrum point136. Thefulcrum point136 of theendoport device160 coincides with a point along the device body where it rests in the incision. The steering device positions the proximal end of theinstrument120 within reach of the user'shand138 which can access and operate controls thereon, independent of adjusting the pivotal position of the instrument, which is performed by the arm. The user's wrist joint effectively isolates movements by thehand138 from movements of the arm part. Thesteering guide119 takes advantage of the isolated movement to operate any proximally-situated controls of the medical instrument simultaneous with adjusting its position in the available working space.
• Thesteering guide119 may comprise an elongatedlongitudinal member122 having a proximal126 and distal128 end, the proximal end126 disposed with abrace123 for attachment to a part of a bodily arm, and thedistal end128 disposed with anendoport device160, configured for attachment to themedical instrument120.
• The elongatelongitudinal member122 is essentially rigid, and at least spans the length between thebrace123 and a point distal to (beyond) thehand138 of the user. It is preferably made from a light weight material such as aluminum, titanium, polymer (e.g. polycarbonate), or composite. It may be formed from a solid rod, hollowed rod, or from a rod with transverse openings. The material used to form the elongatelongitudinal member122 may not inherently posses the requisite rigidity in the rod form, in which case the structure may be strengthened with one or more cross supports. The elongatelongitudinal member122 may be straight at least in part. The distal end126 may be shaped (e.g. curved) to create a volume that accommodates a range of movement by thehand138. The distal end126 may be further shaped (e.g. curved) to bring theendoport device160, in particular the passage therethrough, in co-axial alignment with the longitudinal axis of thelower arm128.
• Thebrace123 attaches the elongatedlongitudinal member122 to a part of the bodily arm of the user. Thebrace123 may be adapted for attachment to any part of the arm, for instance, theupper arm130,lower arm131 orelbow132. Thebrace123 may be attached to the proximal end126 of the elongatedlongitudinal member122 using afixture134 that allows slidable movement of the elongatedlongitudinal member122 relative to thebrace123. Thefixture134 may further be configured to limit or allow pivotal movement of the elongatedlongitudinal member122 relative to thebrace123. Thefixture134 exemplified inFIG. 17 comprises a protruding rigid eyelet through which the elongatelongitudinal member122 passes, and can pivot and slide relative to the eyelet. Thebrace123 may be configured to orientate thelongitudinal member122 essentially parallel to thelower arm131. Thebrace123 may be configured to position theendoport device160 at a point distal to (beyond) thehand138 of the user. Movements of the arm, e.g. theupper arm130,lower arm128 orelbow132 are directly transmitted along the elongatedlongitudinal member122 to theendoport device160 which they are realised as pivotal movements.
• Thebrace123 may be formed from a cylindrical ring, with a central passage in which the arm part lies. It is preferably formed from an inelastic cloth cuff configured to wrap around the arm part, and disposed with a securing means such as one or more Velcro® strips.
• Theendoport device160 is attached to thedistal end128 of the elongatedlongitudinal member122. Theendoport device160 is configured to couple with the longitudinal axis of themedical instrument120. Theendoport device160 may permit slidable and rotational movement of the medical instrument relative thereto, which movements are lockable. Typically theendoport device160 comprises a cylindrical passage in which theinstrument120 rests, and optionally a locking mechanism that holds theinstrument120 in fixed position with respect to theendoport device160. The locking mechanism may comprise a nut or pin, that frictionally contacts and applies locking pressure to the body of the instrument. The central axis of the cylindrical passage of theendoport device160 is preferably substantially co-axially aligned with the longitudinal axis of the lower arm. Theendoport device160 may attach to the elongatedlongitudinal member122 with an adjustable joint configured to lockably adjust the orientation of the central axis of the cylindrical passage relative to the longitudinal axis of the lower arm. The joint may permit rotational movement by theendoport device160 in two or three dimensions.
• The elongatedlongitudinal member122 may be rigidly attached to an open kinematic chain comprising a plurality (e.g. 2, 3, 4, 5, 6 or more) of tandemly arranged, rigid links, connected by lockable joints (e.g. revolute and/or ball and socket), which kinematic chain permits movement of the elongatedlongitudinal member122 when the joints are not locked, and which prevents movement by the elongatedlongitudinal member122 when the joints are locked. The open kinematic chain typically has a base link, rigidly attached at one end to the operating table, and an effector link attached to the elongatedlongitudinal member122. One or more links may be disposed between the base and effector links. It will be understood that, in accordance with kinematic principles, the more joints employed, the more degrees of freedom of movement permitted by thelongitudinal member122 attached to the effector link. Typically the total number of joints is 3, 4, 5, 6 or 7 or more. A 6 joint open kinematic chain provides 6 degrees of freedom in its workspace. The locking mechanism of the revolute joints can be any, including a mechanical, electromagnetic, pneumatic or hydraulic brake, preferably actuated by a foot pedal or lever.
• The steering guide is suitable for use with any medical instrument that would benefit from setting its pivotal orientation, such as the steerable tube of the invention, any steerable tube, or a laparoscope. In general the medical instrument has a longitudinal axis, and a body that is capable of being held by theendoport device160.
• The pivotal movements of themedical instrument120 are actuated by a part of the human arm, for instance, theupper arm130,lower arm131 orelbow132, leaving the hand free to operate the instrument, for instance, levers, buttons, controllers, disposed at the instrument's proximal end. When the instrument is asteerable tube100 of the present invention, the hand is able to operate the controller at the proximal end so changing the position of the tube distal end, in addition to operating any handles e.g. for a distal cutter or gripper, without disturbing the pivotal position of the instrument which is controlled by a separate part of the body i.e. the arm, optionally locked by a lockable kinematic chain.
Lockable Articulated Arm
• Another embodiment of the invention is a lockable articulated arm comprising a plurality (e.g. 2, 3, 4, 5, 6 or more) of tandemly arranged, rigid links connected by lockable joints, having at one end a base link configured for rigid attachment to an operating table, and at the other end, an effector link connected to a lockable ball and socket joint, the ball and socket joint configured for coupling to an endoport device, through which a medical instrument disposed with a longitudinal axis, including, but not necessarily limited to, the steerable tube of the present invention is disposed, which lockable ball joint is further configured to pivot the endoport device relative to the effector link. The lockable articulated arm allows the user to orient the effector link within a working volume and to set the desired position. Having set the desired position in three-dimensional space, the medical instrument disposed on the effector link may be independently pivoted around the ball and socket joint, and the desired pivotal position also locked.
• According to one aspect of the invention, the lockable articulated arm, as shown inFIG. 18, comprising a plurality of tandemly arranged,rigid links172,174,176,178 connected bylockable joints180,182,184, which arm170 permits movement of thelinks172,174,176,178 when thejoints180,182,184 are not locked, and which prevent movement by thelinks172,174,176,178 when thejoints180,182,184 are locked. The articulatedarm170 typically has abase link172, rigidly attached at one end to the operating table171, and aneffector link178 connected at one end to a ball and socket joint152 to which anendoport device160 attaches, and through which an invasivemedical instrument120 disposed with a longitudinal axis, including, but not necessarily limited to thesteerable tube100 of the present invention is disposed. One ormore links174,176, may be disposed between the base172 andeffector178 links. It will be understood that the more joints employed in the arm, the greater the degree of freedom of movement i.e. working space permitted by the terminal end of theeffector link178, and thus by themedical instrument120 attached thereto. Typically the total number of joints is 3, 4, 5, 6 or 7 or more.
• One pair of links is preferably connected by one joint. It will also be appreciated that the type ofjoints180,182,184 employed between thelinks172,174,176,178, whether they be revolute, ball and socket, or a mixture, also influences the volume of the working space of the terminal end of theeffector link178. InFIG. 18, the first joint between thebase link172 and thefirst link174 is revolute; the second joint182 between thefirst link174 and second link176 is a ball and socket joint; the third joint184 between the second link176 andthird link178 is revolute.
• The locking mechanism of thejoints180,182,184 can be any, including a manual mechanical mechanism actuated by a lever185 as shown inFIG. 18, or electromagnetic, pneumatic or hydraulic brake, preferably actuated by a foot pedal. Preferably the joints lock simultaneously.
• The ball-joint port152 is also lockable (FIG. 19), meaning that the pivotal position of theendoport device160 can be set and locked at a position within the range of possible movement of the ball joint. The locking mechanism can be any, including, for example, a pin, screw, or collar that frictionally contacts theball154 when advanced there towards, or acontractable socket156.
• As described earlier, theeffector link178 is attached to one part of a ball and socket joint (e.g. the socket), while the other part of the joint (e.g. the ball) attaches to the endoport device. According to the embodiment depicted inFIG. 19, theball154, having a spherical shape, is provided with adiametric bore158 passing completely through the ball, adapted to support theendoport device160. Thebore158 may be configured to permit no or limited slidable or axial-rotational movement by theendoport device160 relative to theball154. Theball154 may incorporate a locking mechanism allowing slidable movement by theendoport device160 in an unlocked mode, and substantially no slidable or axial-rotational movement by the instrument relative to theball152 in a locked mode.
• Theendoport device160 used in both thesteering guide119 and lockable articulatedarm170 is known in the surgical field. For guidance, a brief description follows. Theendoport device160 comprises ahollow tubular member162 configured for insertion through an incision in a subject (e.g. a patient), open at one end, and is attached at the other end to a head section166 comprising a fitting164 for a source of pressurised gas such as carbon dioxide. The fitting164 may be a Luer fitting, preferably provided with a screw thread. Gas passing through the fitting164 is directed to thehollow tubular member162, thereby permitting inflation of the cavity being surgically accessed when the device is in situ. Thehollow tubular member162 may be disposed with one or more side ports (not shown) for gaseous outlet. The head section163 further comprises a linear passage in coaxial alignment with the central axis of thehollow tubular member162 which passage is also in fluidic connection with the hollow of thetubular member162. The combined cylindrical passage so formed, spanning the head and tubular member is suitable for receiving an invasivemedical instrument120 disposed with a longitudinal axis, including, but not necessarily limited to thesteerable tube100 of the present invention. When used in conjunction with the lockable articulatedarm170 of the invention, part of thehollow tubular member162 of theendoport device160 attaches to the ball andsocket152. As shown inFIGS. 18 and 19, thehollow tubular member162 passes trough thebore158 of the ball153, and contacts the head166.
• The lockable articulatedarm170 is suitable for use with any medical instrument that would benefit from setting a spatial and pivotal orientation, such as the steerable tube of the invention, any steerable tube, or a laparoscope. In general the medical instrument has a longitudinal axis and a body that capable of being held within thebore158 of theball154.
• The particular combination of parts described and illustrated herein is intended to represent only one embodiment of the invention, and is not intended to serve as limitations against alternative devices within the spirit and scope of the invention.

Claims (16)

1. (canceled)

2. A steerable tube, comprising a steering mechanism formed as a hollow elongate tubular member, one end being a controller the other end being an effector comprising a distal bendable part wherein:

the tubular member comprises a plurality of longitudinal members connecting the controller to the effector;

movements of the controller are transmitted via the hollow elongate tubular member to the effector which moves responsive to movements of the controller;

the controller comprises a plurality of actuators controlling movement of the longitudinal members; and

the steering mechanism is configured for omnidirectional control and movement of the effector and for axial rotation of the effector in the bent position.

3. The steerable tube according toclaim 2, wherein the longitudinal members are formed by cutting the tubular member or by cutting a flat sheet that is subsequently bent to form the tubular member.

4. The steerable tube according toclaim 2, wherein the longitudinal members are formed individually.

5. The steerable tube according toclaim 2, wherein the longitudinal members are disposed in alignment with or inclined to a longitudinal axis of the hollow elongate tubular member.

6. The steerable tube according toclaim 2, wherein the longitudinal members are provided as spiral strips.

7. The steerable tube according toclaim 2, wherein a diameter of part of the tubular member progressively increases towards a proximal end of the steerable tube to increase leverage of the controller.

8. The steerable tube according toclaim 2, wherein the plurality of actuators is dismountable from the longitudinal members.

9. A multi jointed steerable tube having a proximal end and a distal end, comprising at least two steering mechanisms,

a first steering mechanism formed as a first hollow elongate tubular member, one end being a first controller the other end being a first effector comprising a first distal bendable part wherein:

the first tubular member comprises a plurality of first longitudinal members connecting the first controller to the first effector;

movements of the first controller are transmitted via the first hollow elongate tubular member to the first effector which moves responsive to movements of the first controller;

the first controller comprises a plurality of first actuators controlling movement of the first longitudinal members; and

the first steering mechanism is configured for omnidirectional control and movement of the effector and for axial rotation of the first effector in the bent position; and

a second steering mechanism formed as a second hollow elongate tubular member, one end being a second controller the other end being a second effector comprising a second distal bendable part wherein:

the second tubular member comprises a plurality of second longitudinal members connecting the second controller to the second effector;

movements of the second controller are transmitted via the second hollow elongate tubular member to the second effector which moves responsive to movements of the second controller;

the second controller comprises a plurality of second actuators controlling movement of the second longitudinal members; and

the second steering mechanism is configured for omnidirectional control and movement of the effector and for axial rotation of the second effector in the bent position;

wherein:

the two tubular members are mutually co-axially arranged; and

the second controller is provided distal of the first controller and the second effector provided proximal of the first effector; or

the second controller is provided proximal of the first controller and the second effector provided proximal of the first effector and distal of the first controller.

10. The multi jointed steerable tube according toclaim 9, wherein the first longitudinal members are formed by cutting the first tubular member or by cutting a flat sheet that is subsequently bent to form the first tubular member, and second longitudinal members are formed by cutting the second tubular member or by cutting a flat sheet that is subsequently bent to form the second tubular member.

11. The multi jointed steerable tube according toclaim 9, wherein the first longitudinal members are formed individually, and the second longitudinal members are formed individually.

12. The multi jointed steerable tube according toclaim 9, wherein the first and/or second longitudinal members are disposed in alignment with or inclined to a longitudinal axis of the hollow elongate tubular member.

13. The multi jointed steerable tube according toclaim 9, wherein the first and/or second longitudinal members are provided as spiral strips.

14. The multi jointed steerable tube according toclaim 9, wherein a diameter of part of the first tubular member progressively increases towards the proximal end to increase leverage of the first controller.

15. The multi jointed steerable tube according toclaim 9, wherein a diameter of part of the second tubular member progressively increases towards the proximal end to increase leverage of the second controller.

16. The steerable tube according toclaim 9, wherein the plurality of first actuators is dismountable from the first longitudinal members and the plurality of second actuators is dismountable from the second longitudinal members.

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