WO2023084305A1

WO2023084305A1 - A multifunctional device for use in atherectomies and related endoluminal procedures

Info

Publication number: WO2023084305A1
Application number: PCT/IB2022/000652
Authority: WO
Inventors: Petrus Antonius Besselink
Original assignee: Petrus Antonius Besselink
Priority date: 2021-11-12
Filing date: 2022-11-10
Publication date: 2023-05-19

Abstract

An endoluminal device, and assembly using the endoluminal device, a method of making an endoluminal device and a method of manufacturing an endoluminal device. The device is a. combination of two concentric tubes, such that interaction by the relative axial movement between them causes one or more of a tangential rotation, drilling or reaming effect. At or close to the distal end of the tubes one or more cutting elements are placed. These cutting elements not only cut into a distal direction, but can also cut or ream into proximal direction. The cutting elements are covered when the device is brought into the lumen, and can be exposed by changing the relative axial position of both tubes, resulting in a change of the gap length between two or more reaming burrs. The size of the reaming burrs may be different, dependent if they are mounted on the inner tube or on the outer tube. Similar segmented cutting elements with the changing function of drilling and reaming can also be mounted on drive shafts which are attached to external drive systems.

Description

A MULTIFUNCTIONAL DEVICE FOR USE IN ATHERECTOMIES AND RELATED ENDOLUMINAL PROCEDURES

TECHNICAL FIELD

The present disclosure generally relates to a multifunctional device used in the treatment of partly or completely obstructed arteries, veins and related body lumens in patients, and more particularly to a hand-held device that gives a good tactile feedback to an operator, can be easily used in combination with known guidewires, guiding catheters, aspiration and flushing systems, which can be easily and relatively inexpensively manufactured and have its function switched from a drilling mode of operation to a reaming mode of operation by a simple movement.

BACKGROUND ART

There are several devices on the market for Chronic Total Occlusions (CTO) treatment, mostly used in combination with a guidewire that brings a guiding catheter close to the obstructed location after which the device is used to open the obstruction, often combined with aspiration and suction of the released debris.

Examples are the Abbott Tomus, the Cordis Frontrunner, the Boston Scientific CrossBoss, the Boston Scientific RotaPro, the Avinger Ocelot, the Reflow Medical Wingman, the Medtronic TurboHawk, the AngioDynamics Auryon, the Philips Spectranetics Turbo Tandem, and the Philips Phoenix Atheromed system, to name a few. The cutting devices can have a sharpened distal end for mechanical cutting and others are working with laser cutting. Normally the distal cutter is still located on a central guidewire, which ensures that the cutter stays close to the center of the lumen and stays away from the inner surface of the wall, which has to remain intact. However, if the central guidewire cannot give enough support to this distal cutting element, it still may cause damage to or even penetrate the wall of the lumen, eventually with fatal effects.

In US Patent 10,405,878, Wasdyke describes a rotational atherectomy device with a motor or turbine driven elongate drive shaft and a distal burr in the shape of a rugby ball, combined with a central extendable penetrating member. This device is known commercially as the Rotapro or Rotablator, in which the distal section of the outer surface of the burr is diamond coated to give it abrasive and cutting properties in distal direction. In US Patent 10,751,082, Zhang describes a cutting element that is covered inside the catheter until it reached the occlusion and then a pull wire bends the catheter, thus causing the cutting element to protrude radially from the catheter surface in a controllable way. When the catheter is moved distally the cutter reams a part of the cross section of the obstruction, and by repeating this axial movement several times after tangential offsets the open lumen can be enlarged.

In US Patent 5,318,576, Plassche describes a rotating expandable basket, with variable diameter (by pushing the basket more or less out of a delivery tube). The struts have a tangential cutting function.

In US Published Application 2010/0125253, Olson describes a device with a dual tip, wherein either the guidewire or a drill tip protrudes from a single distal hole in the catheter.

In US Patent 6,428,634, the author of the present disclosure describes medical devices made of temaiy shape memory alloys with super-elastic plateau stresses that are much higher than for binary alloys, which can be used for achieving higher output forces at identical dimensions, or smaller dimensions at similar output forces. Such alloys can be used for multiple properties, including the higher plateau stresses if in the super-elastic mode, or higher elastic modus if cold worked.

In US Patents 5,885,258, 6,780,175, 7,037,321, 8,052,670 and 8,377,037, the author of the present disclosure describes numerous kinds of medical instruments based on slotted memoiy metal tubing for making flexible and steerable devices. Some examples describe super-elastic tubular baskets for making expandable revolving reamers with cutting struts. In another embodiment an expandable basket, located at or near the distal end of the instrument, can have a centering function to keep a drill tip in the middle of the lumen.

In US Patents 7,776,062 and 8,382,786, the author of the present disclosure describes a self-centering distal anchoring section in a catheter or guidewire which is actuated by a proximal biasing spring that holds two concentric tubes in a preferred axial position. Changing the length of the biasing spring causes a change in the geometry of the distal section. There is place for applying additional devices through the inner tube or over the outer tube, dependent on the application.

In US Patent 5,607,435, the author of the present disclosure describes a medical tool with a nitinol inner tube that has a curved shape when it leaves the distal end of a surrounding catheter tube. This enables movement of the distal end with several degrees of freedom, when the longitudinal movements are combined with a rotation around the length axis. One example mentioned is a steerable drill tip. Upon withdrawal of the inner nitinol tube into the surrounding catheter tube the device is brought into a straight shape again for insertion and removal purposes.

In US Patent 10,441,746, the author of the present disclosure describes a catheter or guidewire with a helical cut with variable width in the tubular wall. Changing the length of this device by a central pull wire or tube causes a controlled tangential revolving of the distal end without the need of having proximal rotation. This is defined as self-torque tip (STT), resulting in a Single Torque Motor (STM).

A problem exists in that most commercially available devices are complicated to manufacture, with expensive motor drives and multiple parts that are assembled. Further there is no device that has a simple solution to prevent the hazardous interaction of the cutting or reaming member with the inner wall of the artery.

DISCLOSURE OF INVENTION

The present disclosure relates to using an endoluminal device in the treatment of partly or completely obstructed body lumens in patients, such as removing plaque or CTOs in arteries and veins. In one form, this device may be used for thrombectomy or atherectomy procedures for opening CTOs. In one form, the device includes a combination of a solid wire and a surrounding tube, while in another as a set of at least two interacting concentric tubes. In one form, one or more segments with abrading, reaming or cutting (collectively, reaming) elements are placed at or close to the distal end of the tubes. These reaming elements are capable of not only cutting in the distal direction, but the proximal direction as well. Sharpened edges, sections, comers or related portions of these elements remain covered while the device traverses the lumen, only to be exposed for use by changing a relative axial position of both tubes that results in a change of the distance between two or more reaming sections or related segments. Depending on which of the tubes they are mounted to, the size and shape of these reaming sections may differ from one another.

According to an aspect of the present disclosure, a multifunction device for performing a drilling mode of operation and a reaming mode of operation in a lesion, obstruction or occlusion of an entirely or partially obstructed body lumen is disclosed. The device includes an elongate inner member having proximal and distal ends the latter of which terminates as a drill tip, along with a first reaming burr at or near its distal end. The first reaming burr has proximal end that defines a cutting edge. The device further includes an elongate outer member that surrounds the elongate inner member, along with a second reaming burr that itself has cutting edge that is facing the cutting edge of the first reaming burr along an elongate axial direction defined by the device. In this way, the first and second reaming burrs define opposing cutting edges between them. The device also includes a tool attached to and located substantially at the proximal ends of both the inner and outer elongate members. By its construction, the tool is capable of controlling one or both of the tangential rotation of both of the first and second reaming burrs, as well as the length of a relative axial gap between the reaming burrs during at least one of the drilling and reaming modes of operation.

According to another aspect of the present disclosure, a method for drilling an opening or enlarging the opening in an at least partially obstructed body lumen is disclosed. The method includes providing a device with an elongate inner member, an elongate outer member and a tool attached to and located substantially at the proximal ends of both the inner and outer elongate members, and performing within the body lumen (upon receipt within the tool of a moving force from a user) at least one of a drilling mode of operation and a reaming mode of operation by a cooperative arrangement between the elongate inner and outer members. The elongate inner member has proximal and distal ends such that the distal end defines a first reaming burr thereon and wherein the first reaming burr has proximal and distal ends where the proximal end defines a cutting edge while the distal end defines a drill tip. The elongate outer surrounds the elongate inner member and has proximal and distal ends where the distal end defines a second reaming burr thereon such that the second reaming burr has proximal and distal ends such that its distal end defines a cutting edge that is facing the cutting edge of the first reaming burr along an elongate axial direction defined by the device; in this way, the first and second reaming burrs cooperate to define opposing cutting edges.

In one embodiment the device is configured as a Double Torque Motor (DTM), wherein the outer tube slides over the inner tube, and wherein the mechanical interaction by the relative axial movement between the tubes causes a reversible tangential rotation in one mode and wherein it can be switched to one or more of a longitudinal drilling or reaming effect in the other mode, without tangential rotation, or if needed including tangential rotation.

It is an object of the present disclosure that devices using reaming burrs for opening occlusions may be composed out of separate reaming burr sections, of which the sharpened cutting parts are covered by causing the reaming bun sections to fit against each other. By separating the reaming burr sections and controlling the gap between these sections, they can be activated for cutting, reaming or related purposes.

Another object of the present disclosure is that by a proper dimensioning of the reaming burr sections the roughened part or teeth of the drilling tip cannot come into contact with the wall of the body lumen.

It is also an object of the present disclosure that separable reaming burr sections are connected to long interacting wires or tubes, of which one or both of the axial and rotational movements can be controlled from a location outside of the patient’s body, for example by use of a motor drive.

Another object of the present disclosure is that at least one of the tubes with the reaming burr sections is configured as an STM, provided with helical cuts that enable revolving of the distal end, without revolving of the proximal end of the same tube.

In yet another object of the present disclosure at least two concentric tubes, each with a helical cut section, each provided with at least one cutting or reaming bit at or near the distal end thereof, cooperate as a DTM when the distal ends are pushed together. If the distal ends are not pushed together, the same device works in a non-revolving mode, wherein reaming is achieved by pulling the entire assembly back and forth.

Another obj ect of the present disclosure is that the STM effect or DTM effect is used for moving one reaming burr or drill tip only.

It is further another object of the present disclosure that on the proximal side a control tool is connected to the device, which may be provided with a preloaded bias spring. By variation of the pre-stress in this spring the different modes of rotational drilling/cutting and axial reaming can be simply controlled. A position indicator on the control tool can give feedback on the status of the distal end, for example if there is contact between the reaming burr sections in the drilling mode, or about the width of the gap between the reaming burr sections when it is in the reaming mode.

It is further another object of the present disclosure that the cutting pattern in the STT-tube wall may be helical over the entire length, but also only over a part of the distal end. The remainder of the length may be un-slotted, or have a cutting pattern that optimizes the flexibility or steerability of the device. In another embodiment of the present disclosure, the device can be inserted over a central guidewire.

In another embodiment of the present disclosure, the central lumen of the device can be used to insert a laser or optical fiber that reaches the distal end for treatment or inspection.

In still another embodiment of the present disclosure, the distal part of the inner tube that holds the distal reaming burr tends to bend away from the length axis of the device, when it leaves the distal end of the outer tube. Upon reaming both burrs will then describe a different path, when moving back and forth through the lesion, thus creating a larger opening for each reaming cycle. This reaming may also be done with variable gap length and if needed it can even be combined with tangential rotation of both reaming burr sections. All these combinations of drilling, reaming and adjusting the gap while reaming or drilling can be chosen, depending on the particular type of treatment needed.

In another embodiment of the present disclosure, the device is inserted through a guiding catheter, which has an inflatable cuff or balloon for centering purposes or to close the gap between the outer surface of the catheter and the inner wall of the body lumen. This enables a safe aspiration, flushing and suction of released debris to protect the patient against particles flowing downstream. Instead of an inflatable cuff, an expandable basket may be attached to the outer distal end of the guiding catheter to locate the device in the middle of the lumen before drilling/reaming is started.

Using the STM or DTM effect is beneficial in that it makes it possible to have rotating parts of the device in the most distal section only, meaning that there is no rotation friction in the majority of the length of the device. This is further advantageous in that there will be less tissue damage to the inner wall of the lumen in which the device is placed.

Embodiments disclosed in the prior patents by the author of the present disclosure may be used in combination with the device of the present disclosure or with components thereof.

These and additional features provided by the embodiments and aspects disclosed herein will be more fully understood in view of the following detailed description, in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

FIG. 1 depicts a first STM-tube with a counter-clockwise helical cut and at its distal end a drill and a first reaming burr;

FIG. 2 depicts a second STM-tube with a clockwise helical cut and at its distal end second reaming burr;

FIG. 3 depicts a schematic drawing of a DTM with the tubes of FIGS. 1 and 2 assembled, while the reaming burrs at the distal ends are not in contact with one another;

FIGS. 4a through 4c depict optional details of the distal end of the first STM-tube of FIG.1 with the first reaming burr and drill situated thereon;

FIGS. 5a and 5b depict optional details of the distal end of the second STM-tube of FIG. 2 with the second reaming burr.

FIGS. 6a through 6c depict schematically three distinctive modes of the DIM of FIG.3 with the first and second reaming burrs in three different relative interactions;

FIG. 7 depicts a schematic view showing the proximal end of the DTM of FIG. 3 with a simple pusher handle for axially moving the first and second STM-tubes relatively, along with a preloaded bias spring that holds the first and second reaming burrs in contact as a way to cover their opposing sharpened edges;

FIG. 8 depict a cross section of a body lumen with a partial occlusion that is being worked upon by the reaming burrs of the device of FIG. 6b;

FIG. 9 depicts the device of FIG. 8 inside a strongly curved artery with a lesion where a tip of the drill is forced towards a more centered position;

FIGS. 10a and 10b depict a cutaway view of the body lumen showing the DTM in the reaming mode of FIG. 8, wherein the distal end of the inner tube assumes a bent shape in order to increase its contact surface with the lesion;

FIG. 11 depicts a partial cutaway view of a telescopic manipulator tool, with two clamps and a preload spring in between such that an operator may bring the DTM into either the drilling or reaming mode; and

FIG. 12 depicts a detail of the knob positions in the slot of FIG. 11 that may be used to impart the various modes of FIGS. 6a through 6c.

MODES FOR CARRYING OUT THE INVENTION

The advantages of the various embodiments of the device disclosed herein will become more apparent after reference to the following description, wherein some embodiments are elucidated. As discussed throughout the disclosure, the device disclosed herein may be used in one of two primary modes of operation, namely a drilling mode and a reaming (or cutting) mode. For the purpose of this description, the words burr, reamer and drill tip correspond to components that may have overlapping functional attributes, including configurations where they may work either individually or in conjunction with one another in order (including working either directly or indirectly on the occlusion) to achieve a certain functional objective. It will be appreciated that such use will be apparent from the context, and that all such variants are deemed to be within the scope of the present disclosure. Drilling may be used for creating an initial starting hole, while a reaming burr may be used to enlarge such a hole by cutting more material out, but it is not strictly distinguished here. Other terms that refer to similar effects are cutting, planing, shaving and slicing, to name a few, and all these effects are deemed to be included within the present disclosure.

There are several options and combinations to use the embodiments as disclosed hereafter.

In US Patent 10,441,746, the author of the present disclosure describes a catheter or guidewire with a helical cut in the tubular wall. In response of changing the length of this helical section by a central pull wire or tube, the result is a controlled tangential revolving around its own length axis of the distal end without the need of having proximal rotation. Optimization of the used material, dimensions of the tube wall, slot width of the helix, the pitch and the number of helical loops leads to a tube that revolves over several turns, and upon unloading it turns back to its original state with sufficient torque output to use for cutting/reaming purposes. This is defined as the STT effect in an STM. Suppose that this first tube has a counterclockwise helical cut. If all dimensions are properly designed, an axial shortening of the helix will result in revolving of the tip over a few full turns. When a second tube surrounds the first one and has also a similar helical cut, but now in clockwise direction, it would tend to revolve in a direction opposite from the revolving of the first tube, if an axial shortening is applied to both tubes simultaneously.

But if both tubes are connected at their distal ends, while the proximal ends can be moved axially in relation to each other, the tendency to revolve will be in the same direction. This is caused by the fact that tension in length of one tube will automatically cause compression of the length of the other tube. Now the output rotation is more pronounced and the output torque is larger as well. Such a set of cooperating tubes with different helical orientations defines the DTM disclosed herein. Thus, the attachment of two STMs at their distal ends create a DTM, provided that the orientation of both helices is different. This principle is used to build a simple self-revolving drilling and reaming system that only exists of two tubes and a few interacting cutting and reaming burrs at or near the distal end. Eventually a proximal biasing spring can be used to bring the device each time back into its starting position, preferably with an automated covering of the sharpened edge cutting sections during the maneuvering into the lumen. With the relative axial movement controlled by a simple tool-based handle which is attached to both proximal ends of the STM-tubes, the device can be moved safely through a lumen until it reaches the occlusion, and then be moved back and forth only axially for reaming without revolving. If needed, it can also be used in a mode with a tangentially revolving tip moving back and forth through a lesion for drilling or reaming purposes. The choice between the two modes is made by the position of a simple proximal pusher handle.

Referring first to FIG. 1, a first flexible STM-tube 100 (hereinafter abbreviated to tube 100) is shown as an elongate inner member with opposing proximal and distal ends. The tube 100 has an outer diameter DI and a drill tip 103 situated at the distal end. In another form (not shown), the drill tip 103 may be made integral with a first reaming burr 104 rather than being a part of the tube 100. In either configuration, the drill tip 103 is secured — either directly or indirectly — to the tube 100, and that all variants are deemed to be within the present disclosure. Counter-clockwise helical cuts 101 are formed over at least a portion of the length of the tube 100 (presently shown as being only near its distal end). The first reaming burr 104 with outer diameter D2 is attached to the tube 100 at or near the distal end and the drill tip 103. With such construction, the tube 100 possesses the capacity to drill through distal movement and to ream (or otherwise cut) through its proximal movement. There may be several sections 101, interrupted with non-cut sections in between or eventually sections 102 with a pattern of slots for increased bending flexibility. Such flexibility improving slot pattern may be used in all embodiments of the present disclosure, but will not be described further, other than to note that the helical sections make a self-revolving effect possible. In one form as shown, the drill tip 103 is sharpened, for example with a set laser cut teeth for drilling purposes, such as when the tube 100 is revolving around its length axis in the drilling mode and traversing a body lumen that will be described in more detail elsewhere. In another form (not shown), the drill bit 103 may have a smooth edge. The reaming burr 104 itself may have a smooth distal edge 105, while its proximal edge 106 may have a sharpened cutting profile; such profile may be used to promote reaming a partial obstruction upon movement through such an obstruction in proximal direction. Although the sharpened profile of the proximal edge 106 may define a circular or wavy circumferential pattern as shown, it will be appreciated that other forms may be used, such as having a pattern of teeth or the like. As will be discussed in more detail as follows, an advantage of providing the first reaming burr 104 with the diameter D2 (which as seen is larger than the diameter DI of the tube 100) is that such a construction guarantees that any sharpened objects formed at the distal end of tube 100 (such as the sharpened cutting profile of its proximal edge 106) cannot cause damage to the inner wall of the lumen by the selfcentering effect of the reaming burr 104.

In one form, the tube 100 may be inserted by sliding it over a guidewire (not shown) in order to help introduce it into a lumen, preferably near its center. Likewise, a guiding catheter (also not shown) may be used, such as with a self-centering basket, inflatable balloon or cuff at its distal end. Although presently shown with a hollow, conduit-like construction, the tube 100 may also be configured as a solid wire (not shown), and that both variants are within the scope of the present disclosure.

FIG. 2 shows a second STM-tube 200 (hereinafter abbreviated to tube 200) is shown as an elongate outer member with opposing proximal and distal ends. The tube 200 has an inner diameter D3 and an outer diameter D4 and a similar cutting pattern as tube 100, but now with a clockwise helical cut 201 plus flexibility increasing sections 201 near its distal end. Tube 200 has a second reaming burr 204 that is attached at or near its distal end. With such construction, the second reaming burr 204 possesses the capacity to ream at its distal side. The reaming burr 204 has a smooth proximal edge 205 and a sharpened distal edge 206 that gives the latter sufficient cutting ability when it encounters a calcified obstruction such that it would have a drilling function if it is moved along with the tube 200 in its distal direction. Diameter DI of tube 100 is small enough to fit inside tube 200 and move axially back and forth smoothly. Tube 100 can also easily rotate inside tube 200 when activated. The outside diameter D5 of reaming burr 204 may be equal to the diameter D2 of reaming burr 104, or diameter D5 may differ from diameter D2 (in one form, larger. The contour of edges 106 and 206 of the reaming burrs 104 and 204 are configured to fit precisely together when the reaming burrs 104, 204 are pushed against each other in the axial direction; this in turn produces a locking effect that prevents relative revolving between the reaming burrs 104, 204. Such locking enlarges the final torque output when the device is used as a DTM. This can be achieved by friction only or by all kinds of shape fits, including engaging protruding teeth, wave patterns and many more.

FIG. 3 shows the device in a partially-assembled form where the slidably movable cooperation of the tubes 100, 200 along the elongate axial dimension of the resulting device is shown. In particular, the device is shown as the DTM 300 where in its present state, the reaming burrs 104 and 204 at the distal ends are axially spaced from one another such that they are not in contact and do not form the aforementioned locking effect. An inner surface (or lumen) 107 formed in the tube 100 is available for any purpose including pressure sensing, visual inspection, use of a guidewire, laser drilling, suction or aspiration purposes, if needed. Tube 200 is pulled back over tube 100, and a gap with free length (which corresponds to a relative axial gap length AL) is created between edges 206 and 106 of the reaming burrs 204 and 104 respectively. In this position, the tubes 100 and 200 can be moved freely back and forth relative to one another, thus changing the relative axial gap length AL and reaming in a non-rotating mode with edges 106 and 206 reaming through the lesion. As noted elsewhere, a separate guiding catheter (not shown) that surrounds both tubes 100, 200 may ensure that edges 206 and 106 stay away from the vulnerable inner wall of the lumen.

The distal end of such a guiding catheter may be provided with an inflatable occluding balloon or cuff that places the device in the center and enables flushing and aspiration of the body lumen. It will be appreciated that a device such as that depicted in FIG. 3 does not always need to be constructed as a combination of two STM-tubes or one STM-tube with a non-STM-tube, in one form as it could also work as a non-revolving device that only moves axially back and forth as a reamer/drill combination. In another form, the proximal end could be mounted on a rotating motor that is located outside the patient’s body. Significantly, the reaming burrs 104, 204 of FIG. 3 may in one form be used with an external drive system (such as in the form of a tool various embodiments of which will be discussed in more detail in conjunction with FIGS.6a through 6c, 7 and 11). In such a configuration, the drive system brings at least the distal ends of the tubes 100, 200 into a tangential rotation mode. Likewise, the drive system is connected at the substantially proximal ends of the elongate inner and outer members, the drive system being configured to be located outside of the body lumen.

FIGS. 4a through 4c provide details of an alternate embodiment of the distal end of the STM-tube of FIG.1. In each of these figures, the drill tip 103 has been removed for clarity.

FIG. 4a shows the end of tube 100 with diameter DI and reaming burr 104 with diameter D2 attached thereto. The distal end of tube 100 is cut under an angle with the length axis, and during revolving it will be able to drill in distal direction. The sharpened proximal edge 106 will have a reaming function when it is moved proximally.

FIG. 4b shows a version of tube 100 with an alternate embodiment of the first reaming burr 400 with a maximum diameter D2 and a sharpened edge 402 on the proximal side. As can be seen, the first reaming burr 400 of this embodiment is more bulbous than the first reaming burr 104 of the embodiment of FIGS. 1 and 3. The surface 401 of the reaming burr 400 may either be entirely roughened with an abrasive layer for drilling or highly polished to ensure that the reaming burr 400 only cuts in proximal direction with edge 402. Preferably the diameter D6 of the sharpened edge 402 is smaller than diameter D2 to ensure that the sharpened edge 402 cannot touch and harm the inner artery wall, even if the tube axis makes a relative angle with the length axis of the body lumen. The proximal side of the first reaming burr 400 may have a concave surface 403 in order to improve the cutting behavior of the sharpened edge 402.

FIG. 4c shows an optional expandable reamer 500 with longitudinal slots 501 that create a basket-like structure with sharpened strut sides 502. At its proximal end 525, the nonslotted section 520 is mounted on a long wire 510, and at the distal end the non-slotted section 522 may have a smooth shape or eventually have some teeth 523 cut into its wall, similar to the teeth shown in the drill tip 103 of FIGS. 1 and 3. The collapsed diameter of the section that corresponds to the basket-like structure is small enough to be moved in and out of the inner lumen of an STT-tube. Such small diameter allows it to also be used in combination with a

DTM device. The revolving basket-like structure can cut distally with teeth 523 and ream with struts 502. FIGS. 5a and 5b give optional details of the distal end of the tube 200 of FIG. 2 with the second reaming burr 600.

In FIG. 5a, the distal end of tube 200 has a diameter D4 which is equal to the diameter of the remainder of the tube 200. Distal end 206 mates with the sharpened proximal edge 106 of tube 100 of FIG. 4a, when the two tubes 100, 200 are pushed together by sliding tube 200 in distal direction over tube 100, which is held in place. As soon as the sharpened proximal edge 106 engages the sharpened distal edge 206, the system can start functioning as a DTM, upon further pushing the tube 200 distally over the tube 100.

In this mode the longitudinal reaming effect of the sharpened proximal edge 106 is annihilated because it is completely covered, but the drilling effect of drill tip 103 of FIGS. 1 and 3 is improved, because the DTM enables drilling with higher torque output in both revolving directions. If diameter D2 equals diameter D4, the entire DTM device has a single uniform outer diameter all over its length, including the two reaming burrs.

FIG. 5b shows a version of tube 200 with a second reaming burr 600 that can cooperate with the first reaming burr 400 of FIG. 4b. The second reaming burr 600 has a distal sharpened edge 602, which has a diameter D8, which is smaller than the maximum diameter D7. This slight radially inward taper-like turn helps to ensure that the sharpened edge 602 is not the most outwardly-projecting portion of the second reaming burr 600 that in turn avoids having the sharpened edge 602 gouge or otherwise penetrate the inner wall of the lumen when tube 200 makes an angle with the length axis of the body lumen. The diameter D6 of cutting edge 402 of the first reaming burr 400 may be equal or preferably smaller than diameter D8 of the burr edge 602. Eventually the curvature of the concave surface 603 is adapted to fit and lock well with the outer surface of the first reaming burr 400 near the edge 402 through feathering in order to cover both sharpened edges 402, 602 substantially completely when both reaming burrs 400, 600 are pushed and locked together. This ensures that the device has a smooth outer surface, which can be moved in and out of the body lumen in a safe and smooth way. When both reaming burrs 400, 600 are separated and moved away from each other in a manner similar to that described in the embodiment of FIG. 3, both sharpened edges 402 and 602 can do their reaming work by moving their respective tubes 100, 200 back and forth through a lesion, also making use of variations in their relative axial position, such as through varying the relative axial gap length AL in a manner similar to that of FIG. 3. FIGS. 6a and 6b give schematic details of the proximal and distal ends of the DTM 300 of FIG. 3 with the proximal ends of tube 100 and 200 clamped in clamps C1 and C2 respectively. When both reaming burrs 104 and 204 are just in contact as seen in FIG. 6a, but without axial forces in between, the free length of the gap between fixed clamp C 1 and movable clamp C2 is defined as Y. Tube 200 can be pulled back proximally over a maximum distance ΔY over tube 100 until both clamps C1 and C2 make contact. This will result in the relative axial gap length AL forming a free space both reaming burrs 104, 204. It will be appreciated that although the absolute values of the lengths ΔY and AL may be equal, the longitudinal elasticity of both tubes 100, 200 may cause differences between these lengths.

FIG. 6b shows that C1 is kept still, while moving C2 back and forth over length ΔY results in a variation of the free space over the relative axial gap length AL and the system is used in the reaming mode between edges 106 and 206 without using the revolving effect. The reaming burrs 104, 204 may rotate slightly because the axial forces caused by friction with the tissue or lesion can cause a minor secondary STT effect.

FIG. 6c shows how the position of clamp C2 is brought to a distance Y+Δ Y to bring the device into the DTM mode, with the first and second reaming burrs 104, 204 of FIG. 3 in tight contact, thus covering the sharpened edges 106 and 206 in a manner generally similar to that of the embodiment depicted in FIGS. 4a through 5b. The two reaming burrs 104 and 204 revolve together around their length axis when the proximal end of tube 100 is held still (such as through clamp C1) and the proximal end of the tube 200 is pushed (such as through the movement of clamp C2) over the tube 100 in a distal direction over the additional length ΔY. The helical section 201 of tube 200 (as shown in FIG. 2) is then compressed, while the helical section of tube 100 (as shown in FIG. 1) is stretched. This results in an output torque Ml and a few revolutions of the common distal part. The number of revolutions depends on the used material, the geometry of the helix, the length change and the demanded output torque Ml . When the actuation over the length ΔY is made smaller again the device will unload and the revolving is reversed towards its starting position with reverse torque M2. This DTM cycle can be repeated as many times as needed. It is evident that a proper fitting shape lock between the two reaming burrs 104, 204 prevents slip between them and improves the torque output. The drilling occurs at the distal tip by a sharpened section such as the drill tip 103 (that is only shown generally in the figure). As can be seen the inner tube will elongate elastically slightly (for example 1 -2 mm per complete DTM cycle) over stroke S during increase of Y+Δ Y, which helps automatically during drilling. When the reaming burrs 104, 204 are separated again by moving tube 200 proximally over tube 100 like in FIG. 6b, the procedure can be combined with the reaming actions as described in FIG. 3. This occurs as soon as the distance between C1 and C2 becomes less than Y.

FIG. 7 gives a schematic overview of one embodiment of the device that is being used in a CTO procedure As shown, the device includes the DTM 300 of FIG. 3 in addition

to a control tool 700 in the form of simple handle with clamps C1 and C2, as well as a preloaded bias spring 710. In one form, a major part of the length may be made of tubing with helical slotted sections, or with other flexible sections 102 and 202 as shown in FIGS. 1 and 2. More distally, where the self-revolving effect is needed, both of the tubes 100, 200 can have the proper helical structure. The simple handle with clamps C1 and C2 is configured to axially move the tubes 100, 200 relative to one another, while the bias spring 710 holds the first and second reaming burrs 104 and 204 in contact with a force F1. This has the effect of covering the corresponding sharpened edges 106 and 206 in the manner depicted in FIG.6c. Small axial movements in the pusher handle over the length ΔY back and forth cause rotation clockwise and counterclockwise of the mating reaming burr sections 104, 204 together, optionally combined with the drill tip 103 and eventually a roughened distal outer surface of burr 104. As long as the bias spring 710 has a length Y1 larger than length Y in FIG. 6a, the reaming burrs 104, 204 will stay in contact with one another.

Applying a greater force to the pusher handle will shorten the bias spring 710 and the self-revolving will stop, as soon as the first and second reaming burrs 104, 204 are no longer in contact, and the sharpened edges 106, 206 are now uncovered and ready for reaming or drilling, as described in FIG. 6b. Preferably the material of the reaming burrs 104, 204 has been made radiopaque to enable an operator to follow the procedure precisely on a screen. In FIG. 7 the proximal end of tube 100 protrudes from the clamp C1 to enable the connection to a Luer lock for attaching other additional devices, for flushing or aspiration purposes, as well as for maneuvering. In one form, a guidewire all the way through the inner lumen of tube 100.

FIG. 8 shows the wall of a body lumen 900 with a partial occlusion 901 and the two tubes 100 and 200, together working as the non-revolving device 800, inserted and active in the mode as shown in FIG. 6b. The entire device can be moved axially back and forth for reaming without rotation. Reaming burr 104 will cut parts of lesion 901 when moved to the proximal direction, followed by reaming burr 204 reaming in distal direction. If the effective cutting diameter of both reaming burrs is different, there will be a multistep reaming behavior. The drill tip 103 will do the revolving forward drilling when the device is used in the DTM mode.

FIG. 9 shows the device 800 of FIG. 8 where the body lumen 900 is in the form of a strongly curved artery with a lesion 901. The shape of the bulbous reaming burrs 400 and 600, as disclosed in FIGS. 4b and 5b, prevents contact between the artery (lumen 900) wall and the sharpened edge portions of the reaming burrs (presently shown in their bulbous variants 400 and 600) and the drill tip 103. Even if the device is guided through the curved lumen 900 as in FIG. 9, the outer edges of the reaming burrs 400, 600 will push the drill tip into a more centered position. As previously noted, the reaming burrs 400 and 600 have maximum diameters D2 and D7 respectively, which keep their sharpened edges at the respective diameters D6 and D8 away from the artery wall, even when reaming as shown in FIG. 8 takes place in a curved occlusion. Optionally there may be a gap between the two sharpened edges 402 and 602, even when the device is in its DTM mode. This can be achieved by mounting a separate distance-keeping tube (not shown) between both reaming burrs 400, 600. In one form, the second reaming burr 600 may be mounted on the tube 200 differently from the version shown in FIG. 5b. Thus, when the tube 200 protrudes a few millimeters from the distal edge of the second reaming burr 600, the gap forms while the device is locked for DTM use.

FIGS. 10a and 10b show a guiding catheter in a body lumen with a lesion where the device is in the reaming mode of FIG. 8, wherein the distal end of the inner tube assumes a bent shape, which has been programmed in the tubing (for example by heat treatment if it is made of Nitinol) for increasing the contact surface with the lesion. The curvature in the distal end of the inner tube may be achieved by mechanical treatment or a so-called shape setting treatment. The distal reaming burr (which as shown is embodied as the second reaming burr 600) will stay mainly in the center of the predrilled longitudinal channel in the lesion. When the device is now pushed through the lesion in distal direction, as shown in FIG. 10a, the proximal burr (which as shown is embodied as the first reaming burr 600) will be pushed slightly in radial direction, thus enlarging the cutting efficiency.

Upon reversal of the reaming movement into proximal direction, the situation as shown in FIG. 10b will become actual. Now the proximal reaming burr will move through the center of the channel, but it will push the distal reaming burr in a radially outward direction, thus increasing the reamed cross section area of the lesion. This procedure of enlarging the opening can be repeated several times, while rotating the reamers to radial positions which were not used before, until the entire length and cross section of the lesion is reached and removed or its size is reduced sufficiently. Optionally the device moves over a central guidewire. Another option is the use of a basket or an inflatable cuff on the distal end of the guiding catheter for one or both of centering and aspiration and suction purposes (not shown).

Although the preset curvature of the distal end of tube 100 is only shown as a single bend in one plane, it may have different curvatures as well, including in more than one plane. Pulling back this bent section into tube 200 will straighten the device again.

FIG. 11 gives a partially opened example of a simple telescopic manipulator tool 110, with two clamps and a preload spring in between in a manner generally similar to that of the tool 700 of FIGS. 6a through 6c and FIG.7. It will be appreciated that either tool 110 or tool 700 may be used with the device disclosed herein, and that the choice of which will be dependent on the need of an operator. Clamp C1 can be locked on tube 100, while clamp C2 is locked on tube 200. Clamp C1 is mounted in a cylindrical outer housing 111, in which a cylindrical insert 112 can move back and forth. Clamp C2 is mounted to insert 112. Between C1 and C2 a preloaded spring 113 (similar in functionality to the spring 710 in FIG. 7) biases the clamps C1 and C2 apart from one another. The tubes 100 and 200 can be inserted into the tool 110 by opening clamps C2 and C1 and sliding both tubes through a short inner telescopic guiding tube 114 until tube 100 reaches C1. Guiding tube 114 prevents insertion problems during moving tube 100 through the center of spring 113 until clamp C1 is reached. Guiding tube 114 is made of two tube sections of different diameter, the smallest one connected to C2, while the largest diameter tube is connected to C1, and slides telescopically over the smaller one. When the tubes 100 and 200 are located inside their respective clamps, C1 is locked first on tube 100. A knob 115 and a slot 116 cooperate with one another in the outer surface of housing 111 to enable an operator to change and lock the relative axial position of both clamps in to bring the device into the drilling or reaming mode. Slot 116 has two longitudinal sections 117 and 118, and two tangential sections 119 and 120. Knob 115 is connected to insert 112 and is used to move clamp C2. First the knob 115 is put in a neutral position before clamp C2 is locked on tube 200 as follows below in the description of FIG. 12.

FIG. 12 gives a detail of the different positions of knob 115 in slot 116, corresponding with the modes described in FIGS. 6a through 6c. First, the mounting of tubes 100 and 200 by clamps C1 and C2 to the tool 110 is done similar to FIG. 6a, wherein the preload spring has length Y and the knob 115 is in the position depicted as A in slot section 119. With only C1 locked, the reaming burrs 104, 204 are put just against each other, but without pushing. Then clamp C2 is locked as well. Now the device can be brought into the drilling mode by moving knob 115 to position B, where spring 113 pushes insert 112 with knob 115 towards position C through longitudinal slot section 117, thus creating the rotation as shown in FIG. 6c. The distance between positions B and C of knob 115 corresponds with the length ΔY of FIG. 6c. In one form, an operator may use thumb movement in order to move the knob 115 back and forth between B and C, thus drilling in two directions. In fact, the spring 113 does the drilling in the direction moving from B to C, while the operator does the drilling in direction from C to B. This can be repeated while moving the device gently through the lesion, until it is crossed completely. At this time, the tool 110 can be switched to the reaming mode by moving the knob 115 through tangential slot 119 from drill section B-C into section A-D in a second longitudinal slot section 118.

By moving the knob 115 towards position D over a length ΔY, the length of spring 113 will become Y-ΔY and the reaming burrs 104 and 204 will be separated in a manner similar to that of FIG. 6b. A side slot 120 enables the user to lock this reaming mode by putting the knob 115 in position E.

Eventually, several additional tangential side slots, such as slot 120 for locking position E, may be used with an elongated slot 118 if there is need for having the choice of reaming with different distances between the reaming burrs 104 and 204 (not presently shown).

The expandable reamer 500 shown in Figure 4c can also be a part of the inner tube 100, located in the gap between the two reaming burrs 400, 600. It can be brought in its collapsed state when the outer tube 200 is pushed over the inner tube 100, covering the stmts of the basket and closing the gap between the reaming burrs 400, 600. Moving the outer tube 200 slowly back will cause a gradual expansion of the reamer (not shown).

Besides the described versions in the text and figures, it is within the scope of the present disclosure that any material or any combination of components or materials can be used in any configuration to make or use devices that have slightly different construction than shown. It will be appreciated to those skilled in the art that numerous combinations of one or more embodiments are possible. It will likewise be appreciated by those skilled in the art that other modifications beyond these embodiments specifically described here may be made without departing from the spirit of the present disclosure. Accordingly, such combinations or modifications and all such variants of the same are within the scope of the present disclosure.

It is noted that the terms “substantially” and “about” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized hereinto represent the degree by which a quantitative representation may vaiy from a stated reference without resulting in a change in the basic function of the subject matter at issue.

It is further noted that terms like “preferably,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

Within the present disclosure, terms such as “preferably”, “generally” and “typically” are not utilized to limit the scope of the claims or to imply that certain features are critical, essential, or even important to the disclosed structures or functions. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the disclosed subject matter. Likewise, it is noted that the terms “substantially” and “approximately” and their variants are utilized to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement or other representation. As such, use of these terms represents the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

Within the present disclosure, the use of the prepositional phrase "at least one of is deemed to be an open-ended expression that has both conjunctive and disjunctive attributes. For example, a claim that states "at least one of A, B and C" (where A, B and C are definite or indefinite articles that are the referents of the prepositional phrase) means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. By way of example within the present disclosure, if a claim recites that a device comprises at least one of a first component, a second component and a third component, and if such device has the first component alone, the second component alone, the third component alone or any combination of the first, second and third components, then component or components satisfies the claim.

Within the present disclosure, certain terms are used to establish a degree of connectivity or related structural, physical or other cooperation between various components, as well as between such components and users. Such terms, such as “associated with” or the like, are understood to form an exclusive or non-exclusive relationship between the components and the user or users to which they refer, and will be understood as one or the other, depending on the context.

Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it is noted that the various details disclosed in the present disclosure should not be taken to imply that these details relate to elements that are essential components of the various described embodiments, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Further, it will be apparent that modifications and variations are possible without departing from the scope of the present disclosure, including, but not limited to, embodiments defined in the appended claims. More specifically, although some aspects of the present disclosure may be identified as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

It will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various described embodiments provided such modification and variations come within the scope of the appended claims and their equivalents.

Claims

1. A multifunction device for performing a drilling mode of operation and a reaming mode of operation in a lesion, obstruction or occlusion of an entirely or partially obstructed body lumen, the device comprising: an elongate inner member having proximal and distal ends the latter of which terminates with a drill tip; a first reaming burr situated substantially at the distal end of the elongate inner member and defining a cutting edge at a proximal end thereof; an elongate outer member having proximal and distal ends, the elongate outer member concentrically positionable around the elongate inner member to be slidably cooperative therewith along an elongate axial dimension of the device; a second reaming burr situated on the elongate outer member, the second reaming bundefining a cutting edge at a distal end thereof such that it is facing the cutting edge of the first reaming burr along the elongate axial dimension of the device such that together the first and second reaming burrs define opposing cutting edges; and a tool attached to and located substantially at the proximal ends of both the inner and outer elongate members, the tool configured to control at least one of (i) tangential rotation of both of the corresponding first and second reaming burrs and (ii) a relative axial gap length between the first and second reaming burrs during at least one of the drilling and reaming modes of operation.

2. The device of claim 1, further comprising indicia formed on the tool, the indicia configured to provide an operator information about the relative axial gap between the first and second reaming burrs.

3. The device of claim 1, wherein the drilling mode of operation is defined by the movement of the elongate outer member over the elongate inner member in an axial distal direction of the device to an extent that the opposing cutting edges of the first and second reaming burrs engage and cover each other such that only the drill tip remains exposed.

4. The device of claim 1, wherein the reaming mode of operation is defined by movement of the elongate outer member over the elongate inner member in an axial proximal direction of the device to an extent that the opposing cutting edges of the first and second reaming burrs become exposed such that the cutting edge of the second reaming burr is placed into the reaming mode of operation when pushed in the distal direction while the cutting edge of the first reaming burr is placed in the reaming mode of operation when pulled in the proximal direction.

5. The device of claim 1, wherein the tool comprises a drive system for bringing at least the distal ends of the elongate inner and outer members into a mode that defines the tangential rotation.

6. The device of claim 5, wherein the drive system is connected at the substantially proximal ends of the elongate inner and outer members, the drive system being configured to be located outside of the body lumen.

7. The device of claim 5, wherein the drive system is located inside the body lumen.

8. The device of claim 7, wherein the drive system comprises at least one Single Torque Motor with a helical cutting pattern.

9. The device of claim 8, wherein the tool is a handheld device with at least one clamp that holds the elongate inner member and at least one clamp that holds the elongate outer member.

10. The device of claim 9, wherein the tool comprises a biasing spring configured to maintain the clamps in an axially spaced-part position relative to one another to define a forward drilling position for the drilling mode of operation.

11. The device of claim 10, wherein the biasing spring is configured to be overcome by an external force such that the biasing spring is shortened to define a reverse drilling position for the drilling mode of operation.

12. The device of claim 7, wherein the drive system comprises at least a Double Torque Motor with a helical cutting pattern defined by elongate inner and outer members.

13. The device of claim 12, wherein the tool is a handheld device with at least one clamp that holds the elongate inner member and at least one clamp that holds the elongate outer member.

14. The device of claim 13, wherein the tool comprises a biasing spring configured to maintain the clamps in an axially spaced-part position relative to one another to define a forward drilling position for the drilling mode of operation.

15. The device of claim 14, wherein the biasing spring is configured to be overcome by an external force such that the biasing spring is shortened to define a reverse drilling position for the drilling mode of operation.

16. The device of claim 1, wherein a geometry defined by the opposing cutting edges of the first and second reaming burrs comprise a shape fit that enables a slip-free torque transfer between both cutting edges when they are in the drilling mode of operation.

17. The device of claim 1, wherein each of the first and second reaming burrs define a smooth outer surface over at least a portion thereof such that an outside diameter defined thereby is larger than the diameter of each their corresponding cutting edges such that direct contact between an inner wall of the body lumen and the cutting edges is avoided.

18. The device of claim 17, wherein a distal portion along the length of the first reaming burr tapers radially inward such that a corresponding portion of the outer surface of the first reaming burr comprises a roughened abrasive surface.

19. The device of 1, wherein a section of the elongate inner member that is located at or near any gap that is present between both the first and second reaming burrs has a curved shape, bending away from the central length axis of the device.

20. The device of claim 19, wherein the device is configured to provide variable tangential positions between the first and second reaming burrs.

21. The device of claim 1, further comprising an expandable reaming or cutting element that expands when: it is located between both the first and second reaming burrs and the relative axial gap between the first and second reaming burrs is opened; or when the expandable reaming or cutting element protrudes beyond the distal end of the first reaming burr.

22. The device of claim 21, wherein the expandable reaming or cutting element is a part of the elongate inner member.

23. The device of claim 1, further comprising a guiding catheter with at least one of a balloon and an inflatable cuff configured to provide at least one of device centering within the body lumen and gap size reduction between an outer surface of the catheter and the inner wall of the body lumen.

24. The device of claim 23, wherein the guiding catheter is configured as at least one of a visual inspection, flushing, rinsing, aspiration and suction device.

25. The device of claim 1, further comprising a guiding catheter comprising an expandable basket attached to an outer distal end thereof.

26. The device of claim 1, further comprising at least one additional device comprising a pressure sensing device, a visual inspection device, a guidewire, a laser drilling device, a suction device and an aspiration device.

27. The device of claim 26, wherein the guidewire is at least partially situated within a lumen defined by the elongate inner member.

28. The device of claim 26, wherein the at least one additional device is internally cooperative with the device by being at least partially situated within a lumen defined by the elongate inner member.

29. The device of claim 26, wherein the at least one additional device is externally cooperative with the device by being secured thereto.

30. The device of claim 1, further comprising a guiding catheter configured with at least one of a light source and camera at or near its distal end.

31. The device of claim 1, wherein the proximal end of the elongate inner member is attached to a Luer lock.

32. A method for drilling an opening or enlarging the opening in an at least partially obstructed body lumen, the method comprising: providing a device that comprises: an elongate inner member having proximal and distal ends the latter of which defines a first reaming burr thereon, the first reaming burr having proximal and distal ends the former of which defines a cutting edge while the distal end defines a drill tip; an elongate outer member concentrically positionable around the elongate inner member, the elongate outer member having proximal and distal ends the latter of which defines a second reaming burr thereon, the second reaming burr having proximal and distal ends the latter of which defines a cutting edge that is facing the cutting edge of the first reaming burr along an elongate axial direction defined by the device such that together the first and second reaming burrs define opposing cutting edges; and a tool attached to and located substantially at the proximal ends of both the inner and outer elongate members; and performing within the body lumen, upon receipt within the tool of a moving force from a user, at least one of a drilling mode of operation and a reaming mode of operation by a cooperative arrangement between the elongate inner and outer members.

33. The method of claim 32, further performing, upon receipt within the tool of a force from a user, at least one of: tangential rotation control of both of the corresponding first and second reaming burrs when the device is in its drilling mode of operation; and control of the length of a relative axial gap between the first and second reaming burrs when the device is engaged in back and forth movement during its reaming mode of operation.

34. The method of claim 33, wherein multiple successive reaming movements are made by repeatedly changing the tangential position of the first and second reaming burr sections within the at least partially obstructed body lumen after each back and forth movement.

35. The method of claim 33, wherein each back and forth movement is taking place simultaneously with the tangential rotation control.

36. The method of claim 33, wherein the length of the relative axial gap is varied during the back and forth movement.

37. The method of claim 36, wherein the length of the relative axial gap that is varied during the back and forth movement takes place simultaneously with the tangential rotation control.