Patent Description:
Endoscopic sinus procedures, including surgery, are commonly used to treat chronic sinusitis. In many procedures, an endoscope is inserted into the nostril along with one or more surgical instruments. In certain procedures the insertion and subsequent withdrawal of a balloon into the tubular sinus passages is required. In other procedures, surgical instruments are inserted to cut and/or ablate tissue in order to improve drainage from the sinus cavity.

In order to reach access points of the various sinus cavities, ENT physicians typically use a tool set with multiple tools specifically adapted for insertion or guiding of instruments, each with a different angle, in order to allow the proper access to the desired site. The physician has to select the correctly angled tool or replace the tip of the tool with the correctly angled instrument, which can be cumbersome and involves additional costs.

It has been suggested to use a steerable or bendable tip for certain ENT tools. However, the flexible ends or tips of these known instruments do not remain rigid so that the physician can apply a force using the side or tip of the instrument, particularly when the tip is in the bent configuration.

It would be desirable to provide a reusable insertion instrument that is adjustably deflectable, but that can still remain rigid once it is bent or deflected so that a physician can apply pressure using the side or tip or the bent end section as necessary for various procedures.

<CIT> describes a medical apparatus and method suitable for remodeling a mitral valve annulus adjacent to the coronary sinus. The apparatus comprises an elongate body having a proximal region and a distal region. The elongate body may be moved from a first configuration for transluminal delivery to at least a portion of the coronary sinus to a second configuration for remodeling the mitral valve annulus proximate the coronary sinus. Further, the elongate body may comprise a tube having a plurality of transverse slots therein.

<CIT> describes an endoscope including a control section and a shaft extending from the control section. The shaft includes a frame having a one-piece tube. The tube includes at least one slot into the tube to form spaced sections on opposite sides of the slot. A first one of the sections includes at least one projection which extends into at least one pocket of a second one of the sections such that the projection and pocket form an over-travel limiter to limit relative motion of the first and second sections relative to each other in at least one direction.

<CIT> describes a bone fixation device. The bone fixation device is provided with an elongate body having a longitudinal axis and having a first state in which at least a portion of the body is flexible and a second state in which the body is generally rigid, an actuateable gripper disposed at a distal location on the elongated body, a hub located on a proximal end of the elongated body, and an actuator operably connected to the gripper to deploy the gripper from a retracted configuration to an expanded configuration. Various configurations are disclosed for allowing a device body to change shape as it moves from a flexible state to a rigid state.

<CIT>describes a system which has an elongate tubular shaft comprising slots spaced apart longitudinally along a length of the elongate tubular shaft. The slots form a gap between proximal and distal sides of the slots to close upon application of force to the elongate tubular shaft. Opposite ends of the slots are separated from each other by a spine portion extending longitudinally along the length of the elongate tubular shaft, where a position and/or shape of the slots varies along the length of the elongate tubular shaft to provide different bending characteristics to different portions of the tubular shaft.

An insertion instrument is disclosed to address the issues with the prior known devices, and in a preferred application, is particularly suited for ENT procedures, such as the insertion of a balloon into a nasal cavity.

The insertion instrument comprises a tube having a proximal end adapted to be gripped by a user and a distal end adapted for insertion. A tip control actuator is located at the proximal end, and the distal end of the tube includes a flexible portion. This flexible portion includes a spine and a plurality of circumferentially extending ribs extending from the spine. The ribs are axially spaced apart from a distal tip toward the proximal end, with the ribs being spaced apart by wedge shaped partial circumferential openings. A widest part of the wedge-shaped openings is circumferentially opposite to the spine. The ribs have first and second axial sides defined by the wedge-shaped openings, with the first axial side of one of the ribs facing the second axial side of an adjacent one of the ribs. For each of the ribs, at least one of the first or second axial sides includes at least one of an axially extending projection or a recess and a facing one of the at least one of the first or second axial sides of an adjacent one of the ribs includes at least one of a complementary mating recess or a corresponding axial projection. At least one tension wire extends from the tip control actuator to the distal tip. This allows a user, by actuating the tip control actuator, to elastically bend/articulate the distal end of the tube to allow for insertion in a curved passage, such as a sinus cavity. At the same time, the projections enter or extend further into the recesses during bending of the distal end maintaining a rigid structure, allowing a sideways or normal force to be exerted by the tip as it is being inserted, which is often necessary in ENT procedures such as inserting a balloon, without the bent distal end of the tube shifting or collapsing. This interlocking arrangement of projections and recesses also provides a smooth inner surface that avoids tearing the balloon during manipulation and insertion.

In a preferred arrangement, the tip control actuator comprises a rotatable grip.

In a preferred arrangement, the tube comprises a guide tube connected to an end tube, with the end tube forming the distal end and including the flexible portion. This allows for the use of different materials for the tube, with each being optimized in terms of function and cost. Here, the end tube is formed of a superelastic material which allows for repeated use of the insertion instrument. In a preferred application, the end tube is made of Nitinol and has a wall thickness of about <NUM> - <NUM>, and a diameter of about <NUM> - <NUM>. However, other sizes and wall thicknesses can be used depending on the particular application.

In a preferred arrangement, the axially extending projections and corresponding complementary mating recesses and/or the recesses and the corresponding axial projections in the plurality of ribs are arranged in at least one axially extending row. Preferably, there are at least two rows of the axially extending projections and corresponding complementary mating recesses and/or the recesses and the corresponding axial projections. In one particularly preferred application, three of the axially extending rows of the axially extending projections and corresponding complementary mating recesses and/or the recesses and the corresponding axial projections are provided on the distal end, with a first one of the rows being located approximately <NUM> - <NUM> degrees from the spine, a second one of the rows being located approximately <NUM> - <NUM> degrees from the spine, and a third one of the rows being located approximately <NUM>-<NUM> degrees from the spine. The recesses and/or corresponding complementary mating recesses of the first and third rows have a curved path extending from the at least one of the first and second axial sides toward the spine, and the projections and/or corresponding axial projections of the first and third rows having a complementary curved shape to the curved path of the respective recesses or corresponding complementary mating recesses. The recesses and/or corresponding complementary mating recesses of the second row extend along a straight axial path and the respective projections or the corresponding axial projections have a complementary shape.

In a preferred arrangement, a clearance in a circumferential direction between axial projections and corresponding complementary mating recesses and/or the recesses and the corresponding axial projections is about <NUM> - <NUM>. This allows the bendable tip to be somewhat rigid to a sideways or normal force, even when bent due to bracing of the axial projections against the corresponding mating recesses and/or the corresponding axial projections against the recesses.

In a preferred arrangement, at least one opening is provided in the distal tip to connect the tension wire.

In a preferred arrangement, at least one of a complementary projection or a mating recess is located in the distal tip facing the first side of an adjacent one of the ribs. This allows for support and alignment of the distal tip with the distal-most rib.

In a preferred arrangement at least some of the axial projections are at least partially located in the corresponding complementary mating recesses or the corresponding axial projections are at least partially located in the recesses, or both, in an unbent state of the distal end of the tube. This allows for better support, guidance, and alignment of the ribs relative to one another during bending.

In a preferred arrangement, upon application of a tension force on the tension wire, the distal tip is deflectable from an unbent state in which the distal tip remains aligned with an axis of the insertion tool, to an intermediate state in which the distal tip is aligned at an angle to the axis and at least some spaces remain between at least some of the first and second axial sides of the ribs, to a fully deflected state in which the first and second axial sides of the ribs contact one another. Preferably, in each of the unbent state, the intermediate state, and the fully deflected state, at least some of the axial projections are circumferentially braced against sides of the corresponding complementary mating recesses and/or the corresponding axial projections are circumferentially braced against sides of the recesses to maintain a rigidity of the distal tip relative to a normally applied force.

In one preferred arrangement, the wedge-shaped openings all have a same shape. However, the shape of the wedge-shaped openings can be varied in order to achieve a variable bend profile. The bend profile can also be adjusted based on an axial width of the ribs.

In one preferred arrangement, at least one of a complementary projection or recess is provided in a part of the tube facing the second axial side of a proximal-most one of the ribs.

In one preferred arrangement, the tip control actuator includes the rotatable grip which has an internal thread, with the rotatable grip being axially fixed but rotatable on the tube. A sleeve with an external thread is provided, with the sleeve being slideable on the tube and the external thread engaging with the internal thread of the rotatable grip. The sleeve further includes an axially extending slot, and a projection connected to the tube extends into the slot to prevents rotation of the sleeve. The at least one tension wire is connected to the sleeve, and rotation of the rotatable grip causes an axial movement of the sleeve to apply tension on the distal tip via the tension wire in order to elastically bend the distal end.

The method of the present invention is defined by the appended claims. A method of producing a bendable tip for an instrument, is provided, which includes: mounting a tube for an instrument in a CNC controlled rotational and axially movable holder of a laser cutting machine, with a distal end of the tube extending from the holder; activating a laser cutter; cutting wedge shaped partial circumferential openings in the tube to define a plurality of radially extending ribs at the distal end of the tube, with the ribs being connected together by an axially extending spine, and the ribs having first and second axial sides; during cutting, forming in each of the ribs in at least one of the first or second axial sides, at least one of an axial projection or a recess, and forming in a facing one of the at least one of the first or second axial sides of an adjacent one of the ribs at least one of a corresponding complementary mating recess or a corresponding axial projection.

In a preferred method, the holder is hollow, and tube stock that is cut to form the bendable tip can be axially advanced out of the holder and then cut to the desired tube length to form the tube, and a cutting process for the next bendable tip can then be carried out on the newly cut end of the tube stock.

In a further preferred aspect of the method, during cutting, at least one of a complementary projection or a mating recess is formed in an axial side of the distal tip that faces the first axial side of a first one of the ribs that is adjacent to the distal tip, with the at least one of the complementary projection or the mating recess being aligned with a corresponding one of the recess or the axial projection of a first one of the ribs that is adjacent to the distal tip.

In a further preferred aspect of the method, during cutting, at least one of a complementary projection or a mating recess is formed in an axial side of a part of the tube facing the second axial side of a last one of the ribs that is adjacent to a proximal part of the end tube, with the complementary projection or the mating recess being aligned with the at least one of the recess or the axial projection on the second axial side of the last one of the ribs.

In a further preferred aspect of the method, in order to form the insertion tool, a tension wire is connected to the distal end, and the tension wire extends through the tube to a tip control actuator located at a proximal end of the tube.

In a further preferred aspect of the method, during cutting, a clearance of about <NUM> - <NUM> is created in a circumferential direction between the axial projections and the corresponding complementary mating recesses and/or the recesses and the corresponding axial projections.

In a further preferred aspect of the method, the end tube is formed from a superelastic alloy, preferably Nitinol.

In a further preferred aspect of the method, after the laser cutting, at least one of electropolishing or abrasive cleaning of the tube is performed. Here electropolishing is preferred due to the enhanced smoothness of the surface finish obtained by this process and the ability to treat all surfaces.

In a further preferred aspect of the method, during cutting, at least one tension wire connection hole is formed at the distal end of the tube opposite to the spine.

In a further preferred aspect of the method, during cutting, rounded openings are formed at corners of the wedge shaped partial circumferential openings adjacent to the spine. Preferably, these rounded openings are oval and have a major axis extending in the axial direction of the tube.

As will be recognized by those of ordinary skill in the art from the present disclosure, the above-noted features can be utilized alone or in various combinations in order to provide enhanced functionality for insertion instruments.

The foregoing Summary as well as the following Detailed Description will be best understood when read in conjunction with the appended drawings. In the drawings:.

Certain terminology is used in the following description for convenience only and is not limiting. The words "front," "rear," "upper" and "lower" designate directions in the drawings to which reference is made. The words "inwardly" and "outwardly" refer to directions toward and away from the parts referenced in the drawings. The terms "approximately" and "about" are intended to cover manufacturing tolerances associated with a particular dimension or range given. These terms and terms of similar import are for ease of description when referring to the drawings and should not be considered limiting. "Axially" refers to a direction along the axis of a shaft or similar object. A reference to a list of items that are cited as "at least one of a, b, or c" (where a, b, and c represent the items being listed) means any single one of the items a, b, or c, or combinations thereof. For the sake of convenience and clarity, the term "and/or" has been used in connection with description of the interfacing projections and recesses so that it is clear that the projections can be on either one of or both of two facing axial sides, and that the opposite one of or both of the two facing axial sides would include recesses in corresponding positions to the projections.

For elements of the invention that are identical or have identical actions, identical reference symbols are used. The illustrated embodiments represent merely examples for how the device according to the invention could be equipped. They do not represent a conclusive limitation of the invention.

Referring to <FIG>, an insertion instrument <NUM> is shown. The insertion instrument <NUM> includes a tube <NUM> having a proximal end <NUM> adapted to be gripped by a user and a distal end <NUM> adapted for insertion. The insertion instrument <NUM> is preferably for use in connection with ENT procedures, such as insertion of a balloon for expanding a sinus cavity. However, it can be used for various other medical or non-medical applications.

In the illustrated embodiment of the insertion instrument <NUM>, the tube <NUM> is formed of a guide tube 12A located at the proximal end that is connected to an end tube 12B, located at the distal end. The end tube 12B includes a flexible portion <NUM>.

As shown in <FIG>, a tip control actuator <NUM> is located at the proximal end <NUM>. This tip control actuator <NUM> comprises a rotatable grip <NUM>. However, other types of tip control actuators <NUM> could be utilized, such as an axially slideable grip.

Referring to <FIG>, in one preferred application, the rotatable grip <NUM> has an internal thread <NUM>. The rotatable grip <NUM> is axially fixed but rotatable on the tube <NUM>. A sleeve <NUM> with an external thread <NUM> is provided, with the sleeve <NUM> being slideable on the tube <NUM> in an axial direction and the external thread <NUM> of the sleeve <NUM> is engaged with the internal thread <NUM> of the rotatable grip <NUM>. The sleeve <NUM> further includes an axially extending slot <NUM>, and a projection <NUM> that is connected to the tube <NUM> extends into the slot <NUM> in order to prevent rotation of the sleeve <NUM> during turning of the rotatable grip <NUM>. At least one tension wire <NUM>, as discussed in further detail below, is connected to the sleeve <NUM>. A further description of the function of tip control actuator <NUM> follows further below.

Still with reference to <FIG> and with further reference to <FIG>, the flexible portion <NUM> at the distal end <NUM> of the tube <NUM> includes a spine <NUM> as well as a plurality of circumferentially extending ribs 34A-34I that extend from the spine <NUM> which are axially spaced apart from a distal tip <NUM> of the end tube 12B toward the proximal end. The ribs are generally referred to as <NUM>, and the specific number of ribs 34A-34I could be varied depending upon the particular application for the insertion instrument <NUM> as well as the amount of bend required from the flexible portion <NUM>. As shown in detail in <FIG> and in further enlarged detail in <FIG>, the ribs <NUM> are spaced apart by wedge-shaped partial circumferential openings <NUM>. A widest part <NUM> of these wedge-shaped openings <NUM> is located circumferentially opposite to the spine <NUM>.

The ribs <NUM> have first and second axial sides <NUM>, <NUM>, best shown in the enlarged detail of <FIG>. These axial sides <NUM>, <NUM> are defined by the wedge-shaped openings <NUM>, with the first axial side <NUM> of one of the ribs, for example rib 34B, facing the second axial side <NUM> of an adjacent one of the ribs, for example rib 34A.

As shown in detail in <FIG> and <FIG>, rounded openings <NUM> are provided at the corners of the wedge-shaped openings <NUM> adjacent to the spine <NUM>. These rounded openings <NUM> are preferably oval, having a major axis extending in a direction of the axis X of the insertion instrument <NUM>.

Still with reference to <FIG>, for each of the ribs <NUM>, at least one of the first or second axial sides <NUM>, <NUM> includes one of an axially extending projection <NUM> or a recess <NUM>, and a facing one of the at least one of the first or second axial sides <NUM>, <NUM> of an adjacent one of the ribs <NUM> includes at least one of a complementary mating recess <NUM> or a corresponding axial projection <NUM>.

As shown in detail in <FIG>, it can be seen that the first rib 34A includes three of the axially extending projections <NUM> on the second axial side <NUM> and the facing first axial side <NUM> of an adjacent rib 34B includes three of the complementary mating recesses <NUM>. Additionally, as can be seen most clearly in <FIG>, the second axial side <NUM> of the first rib 34A includes a recess <NUM> and the first axial side <NUM> of the second rib 34B includes corresponding axial projections <NUM>. While the illustrated embodiment includes both projections <NUM>, <NUM> and recesses <NUM>, <NUM> on both axial sides of the ribs <NUM>, this is not required.

In a preferred embodiment, the axially extending projections <NUM> and the corresponding complementary mating recesses <NUM> and/or the recesses <NUM> and the corresponding axial projections <NUM> in the plurality ribs 34A-34I are arranged in at least one axially extending row 55A, 55B, 55C, indicated in <FIG> and <FIG>. More preferably, there are at least two rows 55A-55C of the axially extending projections <NUM> and the corresponding complementary mating recesses <NUM> and/or the recesses <NUM> and the corresponding axial projections <NUM>. In the illustrated embodiment, three of the axially extending rows 55A-55C of axially extending projections <NUM> and corresponding complementary mating recesses <NUM> and/or the recesses <NUM> and the corresponding axial projections <NUM> are provided. Here a first one of the rows 55A is located approximately <NUM>°-<NUM>° from the spine <NUM>. A second one of the rows 55B is located approximately <NUM>°-<NUM>° from the spine <NUM>. A third one of the rows 55C is preferably located approximately <NUM>°-<NUM>° from the spine <NUM>. The recesses <NUM> and/or the corresponding complementary mating recesses <NUM> of the first and third rows 55A and 55C, and in the illustrated embodiment only the complementary mating recesses <NUM>, preferably have a curved path extending from the at least one of the first and second axial sides <NUM>, <NUM> toward the spine <NUM>. This curved path is shown in detail in <FIG> and preferably describes a radius R which generally corresponds to a bend radius of the tube end 12B at the location of the recesses <NUM> in the illustrated embodiment when it is being flexed. The projections, and in the illustrated embodiment only the axial projections <NUM>, of the first and third rows 55A, 55C also have this complementary curved shape to the curved path of the corresponding complementary mating recesses <NUM>.

Still with reference to <FIG>, the axial projections <NUM> have a clearance in the circumferential direction of <NUM>-<NUM> with the complementary mating recesses <NUM>. Similarly, the corresponding axial projections <NUM> have the same clearance with the recesses <NUM>. In the area of the preferably curved path of the axial projections <NUM> and mating recesses <NUM>, preferably the axial projections <NUM> have a reduced insertion area indicated at <NUM> where a width of the axial projection is made smaller to allow for easier guidance and insertion of the axial projection <NUM> as it enters the mating recess <NUM>. In this area, the clearance can be greater than <NUM>. This also facilitated manufacturing.

As shown in detail in <FIG>, preferably the recesses <NUM> and/or the corresponding complementary mating recesses <NUM> of the second row 55B extend along a straight axial path, and the respective projections <NUM> or the corresponding axial projections <NUM> have a complementary shape.

While one preferred arrangement of the axial projections <NUM> and mating recesses <NUM> along with the recesses <NUM> and the corresponding axial projections <NUM> is shown, those skilled in the art will recognize that other configurations could be utilized and that these projections and recesses do not need to be arranged in rows as illustrated.

In the preferred arrangement, the end tube 12B is formed of superelastic material, such as Nitinol. Preferably, for us in ENT applications for insertion of a balloon catheter, the end tube 12B has a wall thickness of about <NUM>-<NUM>, and a diameter of <NUM>-<NUM>. Those skilled in the art will recognize that these dimensions can be changed for other applications and that other suitable materials may be utilized.

As shown in <FIG> and <FIG>, preferably at least one opening <NUM> is provided in the distal tip <NUM> to connect a tension wire <NUM>. As shown in <FIG>, at least one tension wire <NUM> extends from the tip control actuator <NUM> to the distal tip <NUM> where it is anchored in the at least one opening <NUM>. In one preferred embodiment, two of the tension wires are provided in order to maintain a reduced cross-sectional diameter of the tension wires that projects into the clear open cross-section of the tube 12B while still carrying the necessary loads from the tip control actuator <NUM> to the distal tip <NUM> required for elastically bending the flexible portion <NUM> at the distal end <NUM> of the tube <NUM>.

As shown in detail in <FIG>, at least one of a complementary projection 50T or a mating recess 52T is located in the distal tip <NUM> facing the first axil side <NUM> of an adjacent one of the ribs 34A. Further, as shown in detail in <FIG>, preferably at least one of a complementary projection 53P or recess 51P is provided in a part of the tube 12B facing the second axial side <NUM> of a proximal-most one of the ribs 34I. This is preferably provided in order to provide continuity in the ability to transfer normal forces against the flexible portion <NUM> of the distal end <NUM> of the tube <NUM> when it is in the flexed or bent position as discussed in further detail below.

Still with reference to <FIG>, preferably at least some of the axial projections <NUM> are at least partially located in the corresponding complementary mating recesses <NUM> and/or the corresponding axial projections <NUM> are at least partially located in the recesses <NUM> in an unbent state of the distal end <NUM> of the tube <NUM>. This partial overlap ensures a smooth bending of the flexible portion <NUM> of the tube <NUM> when the tip control actuator <NUM> is actuated by a user.

Referring to <FIG>, upon application of a tension force on the tension wire <NUM> using the tip control actuator <NUM>, the distal tip <NUM> is deflectable from an unbent state in which the distal tip remains aligned with the axis X of the insertion tool <NUM>, to one or more intermediate states as shown in <FIG>, in which the distal tip <NUM> is aligned at an angle to the axis X and at least some space remains between at least some of the first and second axial sides <NUM>, <NUM> of the ribs <NUM>, to a fully deflected state, as shown in <FIG>, in which the first and second axial sides <NUM>, <NUM> of the ribs <NUM> contact one another. In each of the intermediate state and the fully deflected state, at least some of the axial projections <NUM> are circumferentially braced against sides of corresponding complementary mating recesses <NUM> and/or the corresponding axial projections <NUM> are circumferentially braced against sides of the recesses <NUM> to maintain a rigidity of the distal tip <NUM> relative to a normally applied force on the distal tip <NUM>. This is important for certain ENT applications where a normal force must be applied when the distal tip <NUM> is in the deflected position in order to push tissue out of the way as the insertion instrument <NUM> is advanced into a body cavity such as a sinus cavity.

In order to provide different bend profiles for the flexible portion <NUM>, the wedge-shaped openings <NUM> may all have the same shape, as illustrated in detail in <FIG> and <FIG>. Alternatively, at least some of the wedge-shaped openings <NUM> may have different shapes to provide a variable bend profile. This can be done by varying the angle a indicated in <FIG> on some of the ribs at different locations. Alternatively, as is apparent from <FIG>, some of the ribs <NUM> may have different widths which can also be used to adjust the bend profile.

In use, particularly for the embodiment of the insertion instrument <NUM> with the rotatable grip <NUM> that is shown in detail in <FIG>, in order to insert the insertion instrument <NUM> into a body cavity, such as a sinus cavity of a patient, the operator rotates the rotatable grip <NUM> in order to apply tension via the at least one tension wire <NUM> to the distal tip <NUM> such that the flexible portion <NUM> elastically bends into one or more of the intermediate or fully deflected states such as illustrated in <FIG> in order to allow the operator to advance the insertion instrument <NUM> into the desired sinus cavity. Then, an instrument can be inserted through the tube <NUM>, into the sinus cavity. This has particular application in connection with the insertion of a balloon catheter into a sinus cavity.

Referring now to <FIG> and <FIG>, a method for producing a bendable tip for an instrument <NUM> is also provided. The method includes mounting a tube <NUM> for the instrument in a CNC controlled rotational and axially moveable holder <NUM> of a laser cutting machine <NUM>. This step is generally indicated at <NUM> in <FIG>. One example of such a laser cutting machine is the Quantum-Cut Tube machine available from Blueacre Technology Ltd. of Louth, Ireland which provides a high accuracy four axis cutter that allows for cutting and profiling of tubes. Preferably, the moveable holder <NUM> includes a hollow chuck and long lengths of tube stock may be provided by inserting the tube stock through the chuck such that only a small portion of the tube is exposed for laser cutting. The laser <NUM>, shown in <FIG>, is then activated, as indicated in <FIG> at <NUM>. The CNC controlled moveable holder then rotationally and axially moves the tube under the laser cutter in order to cut the wedge-shaped partial circumferential openings <NUM> (as shown in <FIG>) in the tube <NUM> to define the plurality of ribs <NUM> which extend axially from the distal end of the tube <NUM>. As discussed above, the ribs <NUM> are connected together by the axially extended spine <NUM>. This is indicated at <NUM> in <FIG>. During cutting, at least one of an axial projection <NUM> or a recess <NUM> is formed in each of the ribs in at least one of the first or second axial sides <NUM>, <NUM>. This is indicated at <NUM> in <FIG>. Further, during cutting, at least one of a corresponding complementary mating recess <NUM> or a corresponding axial projection <NUM> is formed in a facing one of the at least one of the first or second axial sides <NUM>, <NUM> of an adjacent one of the ribs <NUM>. This is indicated at <NUM> in <FIG>.

Preferably, during cutting, the complementary projections 53T or mating recesses 51T are formed in an axial side of the distal tip <NUM> that faces the first axial side <NUM> of a first one of the ribs 34A, and at least one of the complementary projections 53T or mating recesses 51T is aligned with a corresponding one of the recesses <NUM> or the axial projection <NUM> of the first one of the ribs 34A adjacent to the distal tip <NUM>.

Further, during cutting at least one complementary projection 53P or a mating recess 51P is formed in an axial side of a part of the tube <NUM> facing the second axial side <NUM> of a last one of the ribs 34I that is adjacent to the proximal part of the tube <NUM>. The complementary projection 53P or the mating recess 51P is aligned with the at least one of the recess <NUM> or the axially projection <NUM> on the second axial side <NUM> of the last one of the ribs 34I.

During cutting of the axial projections and mating recesses, a clearance in the circumferential direction of about <NUM>-<NUM> is provided in order to provide for smooth bending operation of the flexible portion <NUM> while still allowing the bracing contact between the respective projections and the recesses so that a normal force can be applied to the distal end <NUM> in use without the flexible portion <NUM> at the distal end <NUM> of the tube <NUM> collapsing or flexing. This is indicated at <NUM> in <FIG>.

Preferably, during cutting, a tension wire connection opening <NUM> is formed at the distal end <NUM> of the tube circumferentially opposite to the spine <NUM>. This allows connection of the tension wire <NUM> to the distal tip <NUM> in a later step. This is indicated at <NUM> in <FIG>.

Preferably, during cutting, rounded openings <NUM> are formed at the corners of the wedge-shaped partial circumferential openings <NUM> adjacent to the spine <NUM>. This is indicated at <NUM> in <FIG>.

Once the cutting of the tube <NUM> is completed, to the extent that this is only a portion of a longer piece of tube stock from which multiple such tubes <NUM> can be formed, the tube stock is advanced through the moveable holder <NUM> until a sufficient length is exposed to form the desired length for the tube <NUM> and the completed tube <NUM> is cut from the end of the tube stock. At that point the next cutting operating for forming the next tube <NUM> can be initiated.

Once cutting of the tube <NUM> has been completed, it is preferably at least one of electropolished or abrasively cleaned in order to remove any sharp edges and smooth over any imperfections in the areas of the laser cutting. Electropolishing is preferred due to the smooth surface finish provided which does not include any abrasive scratch lines due to the electropolishing process used. Alternatively, depending on the particular application for the instrument <NUM>, an abrasive cleaning, for example, in a shaker with an abrasive media could also be utilized.

Once the tube <NUM> is complete, or if the only portion formed using laser cutting is the end tube 12B, this can be assembled with the guide tube 12A to complete the tube <NUM>, and then the tip control actuator <NUM> can be assembled to the tube <NUM>. The at least one tension wire <NUM> is then connected from the at least one connection opening <NUM> and extended through the tube <NUM> for connection to the tip control actuator <NUM>.

The insertion instrument <NUM> then provides the advantage of not requiring separate tips having different bend angles since the construction of the flexible portion <NUM> is specifically designed to allow for the application of a normal force without the distal tip <NUM> being unduly deflected in a manner that would hinder the insertion process, particularly in ENT applications.

Claim 1:
A method of producing a bendable tip for an instrument, comprising:
mounting a tube (<NUM>) for an instrument in a CNC controlled rotational and axially movable holder (<NUM>) of a laser cutting machine (<NUM>), with a distal end (<NUM>) of the tube extending from the holder;
activating a laser cutter (<NUM>);
laser cutting wedge shaped partial circumferential openings (<NUM>) in the tube to define a plurality of radially extending ribs (<NUM>) at the distal end of the tube, the ribs being connected together by an axially extending spine (<NUM>) located circumferentially opposite to a widest part of the wedge shaped openings, and the ribs having first and second axial sides (<NUM>, <NUM>);
during the laser cutting, forming in each of the ribs in at least one of the first or second axial sides, three axial projections (<NUM>) or recesses (<NUM>), and forming in a facing one of the at least one of the first or second axial sides of an adjacent one of the ribs three corresponding complementary mating recesses (<NUM>) or corresponding axial projections (<NUM>),
wherein the axially extending projections and corresponding complementary mating recesses and/or the recesses and the corresponding axial projections in the plurality of ribs are formed in axially extending rows;
characterised in that the axially extending rows consist of a first one of the rows (55A) which is located approximately <NUM> - <NUM> degrees from the spine, a second one of the rows (55B) which is located approximately <NUM> - <NUM> degrees from the spine, and a third one of the rows (55C) which is located approximately <NUM> - <NUM> degrees from the spine, wherein the recesses and/or corresponding complementary mating recesses of the first and third rows have a curved path extending from the at least one of the first and second axial sides toward the spine, and the projections and/or corresponding axial projections of the first and third rows have a complementary curved shape to the curved path of the respective recesses or corresponding complementary mating recesses.