Patent Description:
Some ultrasound probes are designed for imaging from within the body, including catheter probes and transesophageal echocardiography (TEE) probes. In these probes the imaging transducer is located at the tip of the probe, which is generally designed to be articulated by the operator so as to obtain the desired view. The preferred way to articulate the probe tip, particularly in the case of TEE probes, is by means of a distal section of the catheter or gastroscope referred to as a bending neck. The bending neck is formed by a series of links which are pivotally connected to each other. This enables each link to move slightly with respect to its adjoining links and hence the entire section of links can be made to controllably articulate over a substantial angle of bending. Control of the articulation is done by cables extending through the probe and the bending neck which are wrapped about the shaft or pulley of a control knob or motor in the control unit at the proximal end of the probe. As the operator turns a knob or actuates a motor, a desired cable is pulled, which bends the articulating neck section of the probe. Generally the pivot axis between links alternates by <NUM>° from link to link so that some axes can bend in the <NUM>°-<NUM>° directions while the others can bend in the <NUM>°-<NUM>° directions. The use of two controls and control cables for these two axis directions enables the operator to articulate the bending neck in any of these directions or any direction in between. The links and hence the bending neck is hollow, enabling the wiring for the transducer at the distal tip as well as other items such as guide wires and surgical tools to pass through the probe for operation at or through the tip of the probe.

The fabrication and assembly of a bending neck for an articulating probe can be painstaking and costly. Each link of the neck must be individually formed, then the links are joined by pins or rivets so that they will pivot with respect to each other.

In <CIT> it is there disclosed a bending portion of an endoscope that includes a bending piece set in which a plurality of bending pieces are continuously provided by forming a convex portion on a first bending piece and a concave portion on a second bending piece by cutting a rigid pipe. The convex portion and the concave portion form an engagement portion that pivotably couples adjacent bending pieces to each other.

Patent application publication <CIT> relates a method for manufacturing a bendable tube, which is preferably envisaged for an endoscopic instrument. First, a tube is separated into several tube sections in a manner such that adjacent tube sections engage into one another with a positive fit in the axis direction of the tube. After the separation of the tube into several tube sections, means for providing a positive fit transversely to the axis direction of the tube are peripherally arranged on the regions of the tube sections, which are situated in engagement with one another.

It is desirable to have an easier and less costly way to build a bending neck, yet still have the wide range of articulation and articulation control which users demand.

This object is solved by the independent claims.

In accordance with the principles of the present invention, a bending neck for a controllably articulating ultrasound probe is provided which is formed from a single tube or nested tube set. The tube is etched or machined to form individual, pivoting links. A groove formed in one of the tubes of the nested tube set, or indentations in a single tube provide the control cable passageway. The bending neck curvature is formed to be variable, as by the use of movable bending points, multiple control cable anchor points, varying pivot axis spacing, and multi-durometer neck sheaths.

Referring first to <FIG>, a single piece bending neck <NUM> for an articulating ultrasound probe is shown which is formed of two concentric tubes, generally made of a metal such as stainless steel. The inner tube 10b fits tightly within the outer tube 10a. Before insertion, two longitudinal grooves <NUM> are formed on opposite sides along the length of the outside of tube 10b. These grooves form passageways for control cables that control the articulation of the bending neck as described below. The grooves <NUM> are clearly shown in the cross-sectional view of <FIG>. With the two tubes concentrically positioned, they are then cut into separate links <NUM> by laser cutting toward the longitudinal axis of the tube or by another machining technique. The links are formed so as to remain movably connected to each other, as by lobes <NUM> extending from one link to the next and located on opposite sides of the links. These lobes and the spacing between the links formed by the machining process enable the adjacent links to move and pivot with respect to each other about axes extending through opposing lobes on opposite sides of the links. While each link may only pivot a small angle with respect to its neighbor, a number of successive links forming a bending neck may together bend in a considerable curve. This is the desired articulation, significant enough to be able to position the distal end of the probe where needed, but not sharp enough at any articular point so as to bind the wires, tools, and other items passing through the central lumen of the bending neck. <FIG> illustrates a second implementation of a single piece bending neck, this time using just a single tube <NUM>'. The tube <NUM>' is machined into separate connected links as described above, the grooves <NUM> between separate links being shown in this drawing. Since the inner tube used for the control cable groove is not present in this single tube implementation, a series of ring-like indentations <NUM> are formed on opposite sides of the tube to convey the control cables through the bending neck. Two parallel cuts are made through the tube wall, then the area between the cuts is pressed inward, forming the indentations as clearly shown in the cross-sectional view of <FIG>. The indentations are formed on the tube sides which are <NUM>° around the tube from the lines of pivot lobes <NUM>, which are on the top and bottom and cannot be seen in the view of <FIG>. As the control cables passing though the indentations on opposite sides of the tube are pulled after being anchored at the distal end of the bending neck. They will respectively cause the neck to bend into and out of the plane of the drawing of <FIG>.

There are a number of ways that the bending of a bending neck of the present invention can be controlled and adjusted. One control technique is to control the deflection point from which the bending takes place. <FIG> illustrates a technique in which a rigid member <NUM> is located in the bending neck with its distal end at the desired deflection point. In this case the rigid member is a tube <NUM> and this partially cut-away view shows links to the left of the tube <NUM> which are free to pivot about their pivot lobes, while the links through which the tube is located are immobilized from pivoting. The position of the deflection point is adjustable by adjusting the extension of the rigid member <NUM> into and out of the bending neck.

The angle subtended by the curvature of a section of the bending neck can be set by selectively determining the lengths of individual links as illustrated by the bending neck <NUM> of <FIG>. In this implementation the links to the left with pivot lobes <NUM> are relatively short and the length of these links can bend with a relatively shorter radius of curvature. The larger links to the right with the pivot lobes <NUM> will bend maximally with a relatively larger radius of curvature. In addition, the different size links have different moments, which determine which set of links will bend first when commonly controlled. The smaller links with the pivot lobes <NUM>, having smaller moments, will bend first. This is useful, for instance, when the placement of a transducer at the distal tip of the smaller links (left side of the drawing) is being controlled. The articulation of both sections of the bending neck is set to approximately the desired position by pulling relatively forcefully on the control cables in the grooves <NUM> and thereby causing both sections to bend. With the transducer near its desired position, light pulling of the cables is used to move only the distal section of smaller links to finely adjust the final desired position of the transducer.

The degree of pivoting between adjacent links is a function of the groove that is machined through the tube to form separate links. <FIG> is a partial side view of a portion of a bending neck where separate links <NUM> have been formed by machining groove <NUM> through the tube. The two links can pivot around pivot lobe <NUM> by the width of the groove <NUM>, opening and closing the groove <NUM>° on either side of the axis of the pivot lobes. If greater pivoting is desired the groove can be machined with a tapered width with a maximum opening of theta above and below the pivot lobes. The relative pivoting of the adjacent links is thereby increased to the dimension of angle theta.

Another technique for providing variable bending of a bending neck is to enclose the bending neck in a sheath with a variable durometer. <FIG> illustrates a sheath <NUM> over a bending neck with a variable durometer from the distal end to the left to the proximal end of the bending neck. The sheath is relatively stiffer (higher durometer) to the right, which becomes less stiff toward the distal end of the sheath. When the control cables are actuated to bend the bending neck, the distal end will bend first and more easily than the higher durometer proximal section of the bending neck. The durometer can be set by the choice of materials used along the length of the sheath. Another way to achieve the same result is to vary the thickness of the sheath material along the length of the sheath. The dashed lines <NUM> in <FIG> indicate that the sheath <NUM> is thicker toward its proximal (right) end than it is toward and at the distal end. Yet another way to achieve the same result is through the way in which the sheath is affixed to the bending neck. In the example of <FIG> the sheath <NUM> is tacked to the bending neck at closely spaced points <NUM> along the proximal portion of the bending neck, and is tacked to the bending neck at more widely spaced points <NUM> along the distal portion of the bending neck. This will cause the distal portion of the bending neck to bend more easily and readily than the proximal portion.

In some implementations it may be desirable to controllably bend a section of a bending neck at some times, and lock it in an unbent configuration at others. <FIG> illustrates an implementation of this feature using the embodiment of <FIG>. In this case there are two sets of control cables, <NUM>-<NUM>' and <NUM>-<NUM>', extending through the control cable passageways <NUM>. The ends of cables <NUM>-<NUM>' are anchored by attachment to the distal link (leftmost) of the bending neck <NUM> as shown by anchor points <NUM> and <NUM> in <FIG>. In <FIG> the inner tube 10b has been removed for clarity of illustration. The ends of the other set <NUM>-<NUM>' of cables are anchored to link <NUM>', the first link following those with pivot lobes <NUM>, as shown by anchor points <NUM> and <NUM>. When each pair of cables is pulled and relaxed in complementary fashion, the corresponding section of the bending neck is bent in the plane of the drawing, cable set <NUM>-<NUM>' controlling the distal (small link) section and cable set <NUM>-<NUM>' controlling the proximal (larger link) section. But when both of cables <NUM>-<NUM>' are pulled in unison, the links of the proximal section are pulled together and locked into a straight configuration as shown in <FIG>. The distal section of the bending neck can still be controllably articulated by use of cables <NUM>-<NUM>'. When cables <NUM> and <NUM>' are pulled in unison, the entire bending neck is locked in a straight configuration. Thus, by using multiple control cables and selected anchor points, different sections of a bending neck can be locked or articulated.

In the implementation of <FIG> the pivot lobes are all on the front and back of the bending neck, which allows both articulating sections to be curved in the same plane, the plane of the drawing. A single set of control cable passageways <NUM> accommodates both sets of cables for this articulation. <FIG> illustrates an implementation in which pivot lobes <NUM> are formed in the front and back sides of the tube and hence their pivot axes are all normal to the plane of the drawing. The pivot lobes <NUM> of the proximal section of the bending neck, however, are formed on the top and bottom of the tube and have their pivot axes parallel to the plane of the drawing. This means that the distal section with pivot lobes <NUM> can be curved in the plane of the drawing whereas the proximal section of links can be curved orthogonally into and out of the drawing plane. To control these different actions different sets of control cables are used. Cables <NUM> and <NUM>' extend through cable passageways <NUM> and are anchored at the ends at anchor points <NUM> and <NUM>. These cables control the articulation of the distal (leftmost) section of the bending neck. The control cables <NUM> and <NUM>' for the proximal section of the bending neck are oriented <NUM>° around the circumference of the tube from cables <NUM> and <NUM>'. These control cables must pass through their own, differently positioned control cable passageways oriented <NUM>° relative to passageways <NUM>. These control cables <NUM> and <NUM>' are anchored at the distal end of the section of links they control as shown by cable <NUM> anchored at anchor point <NUM> in the cutaway view of <FIG>. (Cable <NUM>' and its anchor point are cut away in this view. ) When cables <NUM>-<NUM>' are pulled the distal section of links is articulated or locked, and when cables <NUM>-<NUM>' are pulled the proximal section of links is controlled.

<FIG> are perspective views of an articulating ultrasound probe of the present invention. This probe has two straight, non-articulating sections <NUM> and <NUM> and two articulating sections <NUM> and <NUM>. Like the implementation of <FIG>, the articulating sections <NUM> and <NUM> articulate in the same plane, the horizontal plane H of the drawings. In <FIG> the short articulating section <NUM> is curved by control of its cables anchored at the distal end of section <NUM>. In <FIG> the cable set anchored at the distal end of section <NUM> has been used to articulate section <NUM>. Since all articulation is in the same plane, the pivot lobes of both sections are on the same sides of the section, and only a single pair of cable passageways is necessary for the control cables of both sections.

<FIG> are perspective views of another articulating ultrasound probe of the present invention, this one implementing articulation in two planes as in the case of <FIG>. Like <FIG>, the articulating section <NUM> of <FIG> has its pivot lobes, pivot axes, and control cable passageways oriented <NUM>° around the circumference of the tube as compared with those of articulating section <NUM>. As <FIG> illustrate, the distal section <NUM> can be controllably articulated up and down in the vertical (V) direction.

Claim 1:
An articulating neck (<NUM>) for an ultrasound probe comprising:
- a plurality of separate pivotally-connected links (<NUM>,<NUM>'),the links being formed from a tube (10b, <NUM>' ) which has been machined with grooves (<NUM>) extending through the wall of the tube by machining toward the longitudinal axis of the tube, wherein each link comprises a pair of pivot lobes (<NUM>, <NUM>) defined by the machined grooves and located on opposite sides of the link, wherein the pivot lobes of each link extend into an adjoining link and enable the two links to pivot with respect to each other while remaining connected to each other; wherein a first section of consecutive links (<NUM>, <NUM>') in the direction of the longitudinal axis exhibit the same length in the direction,
characterized in that the articulating neck further comprises a pair of control cables (<NUM>-<NUM>', <NUM>-<NUM>') configured for controlling the articulation of the plurality of separate pivotally-connected links;
further comprising a second section of consecutive links (<NUM>, <NUM>') in the direction of the longitudinal axis,
wherein the links of the second section all exhibit the same length in the direction which is different than the length of the links of the first section, wherein the first section is a distal section of the articulating neck, and the second section is a proximal section of the articulating neck,
wherein the pair of control cables is a first pair of control cables (<NUM>-<NUM>'), each control cable (<NUM>-<NUM>') of said first pair being anchored to a respective anchor point (<NUM>, <NUM>) of a most distal link (<NUM>) of the distal section, and
wherein the articulating neck further comprises a second pair of control cables (<NUM>-<NUM>'), each control cable (<NUM>-<NUM>') of said second pair being anchored to a respective anchor point (<NUM>, <NUM>) of a distal link (<NUM>') of the proximal section,
wherein said links are so configured such that when both cables (<NUM>-<NUM>') of the second pair are pulled in unison, the links of the proximal section are pulled together and locked into a straight configuration, and when the cables of the first pair (<NUM>-<NUM>') and the second pair (<NUM>-<NUM>') are pulled in unison, the entire bending neck is locked in a straight configuration.