FIELD AND BACKGROUND OF THE INVENTION
The present invention generally relates to apparatus and methods for tissue disruption, and more particularly to apparatus and methods for tissue disruption with a tissue disrupting element, such as a shaft, that may be flexible.
Minimally invasive and percutaneous procedures, which are performed through a small orifice in the skin, limit the size of the surgical tools and implants that are used. Implants that have small cross sections are used such that they can be inserted easily through a small orifice in the skin and be formed into their final functional expanded shape at the intended implantation site in the body.
In order to first insert an implant for spinal surgeries such as interbody fusion, motion preservation and vertebral augmentation in a minimally invasive procedure, it is necessary to first clear space for the implant by disrupting tissue. The process of tissue disruption, although necessary, may itself cause trauma and necessarily damages tissue. Being able to predetermine the amount and the location of the disrupted tissue is vital.
In addition, precise control over the location of an implant for spinal surgery is vitally important to the success or failure of a spinal surgery. Undesired movement of the implant after placement, imprecise placement, improper or imprecise opening, expanding or other forming of the implant after insertion can result in the implant not being precisely where the user intended the implant to be and this can contribute to imperfect fusion. Another problem is avoiding impinging on the spinal cord by the implant or tissue disruption. Differences of a millimeter can change an otherwise successful surgery into an unsuccessful surgery. Many prior art methods and apparatuses have been developed to control the exact placement and opening of implants, such as those used in surgery, for example spinal surgery.
An additional problem is that the surgeon might insert the implant properly but the implant might not do what is desired of it. For example, the implant might sink into the bone tissue (subside) so that even if the implant is supposed to deflect and thereby distract to a certain height the space between vertebral bodies, the presence of the implant and its deflection might not translate into the desired distance between adjacent vertebral bodies due to the subsidence.
An additional problem is the need to remove the disrupted tissue without causing additional trauma.
There is a compelling need for a tissue disruption device that can control the location and amount of disrupted tissue. It would be especially advantageous if such a device and method would solve the above problems.
SUMMARY OF THE PRESENT INVENTION
One aspect of the present invention is a tissue disruption device, comprising a deflectable elongated tissue disrupting element rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state, the tissue disrupting element rotatably anchored at a distal location and deflectable into a curved configuration, a rotary drive configured to rotate the tissue disrupting element around its central axis in the straightened state and in the curved configuration.
A further aspect of the present invention is a method of disrupting target tissue in a human or animal body, the method comprising rotatably anchoring at a distal location a deflectable elongated tissue disrupting element to a support element, the tissue disrupting element rotatable around its central axis; the central axis being a longitudinal axis when the disrupting element is in a straightened state; introducing the deflectable elongated tissue disrupting element and support element into the body; and deflecting the tissue disrupting element into a curved configuration while rotating the tissue disrupting element around its central axis, so as to disrupt target tissue.
A still further aspect of the present invention is a method of disrupting tissue of an intervertebral disc of a human or animal body, the method comprising (a) introducing into the human or animal body a deflectable elongated tissue disrupting element, the tissue disrupting element rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state, the tissue disrupting element anchored at a distal location; (b) deflecting the tissue disrupting element into a curved configuration while the tissue disrupting element is rotating around its central axis and anchored at the distal location, in order to disrupt a volume of tissue within a space occupied by the intervertebral disc while leaving at least an arcuate volume of tissue of the intervertebral disc; and (c) implanting the implant so that the implant is enclosed by the at least arcuate volume of tissue of the intervertebral disc.
A yet still further aspect of the present invention is a method of disrupting tissue of an intervertebral disc of a human or animal body, the method comprising (a) introducing into the human or animal body a deflectable elongated tissue disrupting element rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state, the tissue disrupting element anchored at a distal location, the tissue disrupting element having an elongated element rigidly and helically wound around the tissue disrupting element; (b) predefining a volume and location of tissue for disruption by configuring a support element attached to the tissue disrupting element; and (c) deflecting the tissue disrupting element into a curved configuration while the tissue disrupting element is rotating, in order to disrupt a volume of tissue within a space occupied by the intervertebral disc while leaving at least an arcuate volume of tissue of the intervertebral disc.
A still further aspect of the present invention is a tissue disruption device, comprising a deflectable elongated tissue disruptor rotatable around its central axis, the central axis being a longitudinal axis when the tissue disruptor is in a straightened state, the tissue disruptor rotatably anchored at a distal location and deflectable into a curved configuration, the tissue disruptor including a helical element that defines a volume of space radially inward of the helical element for accumulation of disrupted tissue; and a rotary drive configured to rotate the tissue disruptor element around its central axis in the straightened state and in the curved configuration.
Another aspect of the present invention is a tissue disruption device, comprising a deflectable elongated tissue disruptor rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state, the tissue disruptor rotatably anchored at a distal location and deflectable into a curved configuration, and a rotary drive configured to rotate the tissue disruptor around its central axis in the straightened state and in the curved configuration, wherein the tissue disruptor is deflectable into the curved configuration by axially moving a movable pivot toward the distal location, the movable pivot defining a proximal end of the curved configuration of the tissue disruptor.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, descriptions and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments are herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1A is an isometric view of a tissue disruption device in a straightened state, in accordance with one embodiment of the present invention;
FIG. 1B is an isometric view of the device of FIG. 1A in its straightened state from the top showing two degrees of freedom for the tissue disruption device and assembly, in accordance with one embodiment of the present invention;
FIG. 2A is an isometric view of a tissue disruption device wherein the tissue disrupting element (and assembly) is in a curved configuration and utilizing a fixed joint allowing a wider range of motion for the tissue disrupting element (and assembly), in accordance with one embodiment of the present invention;
FIG. 2B is a view of a tissue disruption device of FIG. 2A wherein the tissue disrupting element (and assembly) is in a curved configuration and has swayed, in accordance with one embodiment of the present invention;
FIG. 3A and FIG. 3B are isometric views of a tissue disruption device and integrated support element including the rotary drive and handle, in accordance with one embodiment of the present invention;
FIG. 4 is an enlarged view of the distal portion of FIGS. 3A-B with a pushing component of the support element, in accordance with one embodiment of the present invention;
FIG. 5 is an enlarged view similar to FIG. 4, except without the pushing component and without a flexible shaft of the tissue disrupting element, with openings in the support element to accommodate a wide elongated element, in accordance with one embodiment of the present invention;
FIG. 6 is a top plan of a vertebral body (“VB”) including a disc annulus and nucleus pulposus, and showing a distal portion of a tissue disruption device partly positioned in place on the vertebral body, in accordance with one embodiment of the present invention;
FIG. 7 is a view similar to FIG. 6 except showing more of the distal portion of the device positioned in place, in accordance with one embodiment of the present invention;
FIG. 8 is a view similar to FIGS. 6-7 except with the distal portion of the device fully in place and where the tissue disrupting element (and assembly) in a straightened state is concealed from view, in accordance with one embodiment of the present invention;
FIG. 9A, is a view similar to FIG. 8 except revealing a tissue disruption element (and assembly) deflected to the curved configuration, in accordance with one embodiment of the present invention;
FIG. 9B is an isometric view depicting a distal portion 10A of tissue disruption device 10 with the tissue disrupting element 20 deflected horizontally (laterally) to its curved configuration with the aid of a C-shaped support element, in accordance with one embodiment of the present invention;
FIG. 10A shows an exploded view of a distal portion 10A of tissue disruption device 10 including a C-shaped support element and a remainder of the tissue disruption device that includes a tissue disruption assembly, a fixed pivot and a portion of the support element, in accordance with one embodiment of the present invention;
FIG. 10B is an end view of a distal portion 10A of a tissue disruption device 10, in accordance with one embodiment of the present invention;
FIG. 11 is an isometric view of wire mesh helically wound around the central axis of a tissue disruption device and forming the tissue disrupting element, in accordance with one embodiment of the present invention;
FIG. 12 is a side view of a representative section (portion) of the wire mesh tissue disrupting assembly shown in FIG. 11, in accordance with one embodiment of the present invention;
FIG. 13 is an isometric view of wire mesh fitted over a flexible shaft, in accordance with one embodiment of the present invention;
FIG. 14 is an isometric view of wire mesh as in FIG. 11 without being fitted over a flexible shaft with the differently-shaped wire(s) being curved, such as having a V-shaped cross-section, in accordance with one embodiment of the present invention;
FIG. 15 is a flow chart showing a method, in accordance with one embodiment of the present invention;
FIG. 16 is a flow chart showing a further method, in accordance with one embodiment of the present invention;
FIG. 17 is a flow chart showing a still further method, in accordance with one embodiment of the present invention;
FIGS. 18A and 18B are schematic isometric views of an alternative implementation of a tissue disrupting element including a plurality of rotary segments in a straightened form and an arched form, respectively, in accordance with one embodiment of the present invention;
FIG. 19A is a schematic isometric view of a tissue disrupting element similar to that of FIG. 18B but employing segments mounted on a common flexible shaft, in accordance with one embodiment of the present invention;
FIGS. 19B and 19C are schematic side and cross-sectional views illustrating the mounting of segments on a common flexible shaft according to the principles of FIG. 19A;
FIG. 20 shows an isometric view of an assembly of a helical spring connected to a flexible shaft, in accordance with one embodiment of the present invention;
FIG. 21 shows an enlarged view of the tissue disrupting element of FIG. 20 including a ball configured to interface with a socket to form a joint, in accordance with one embodiment of the present invention;
FIG. 22A shows a fragmentary view broken at line A-A of FIG. 21 and shows the gap defined by volume V between the spring and the flexible shaft, in accordance with one embodiment of the present invention;
FIG. 22B shows an end view taken along line A-A of FIG. 21, in accordance with one embodiment of the present invention;
FIG. 23 shows an isometric view of the device where the assembly of FIG. 20 is inside a tubular support element and the pivot ball is positioned in a socket on the inside of the tip, in accordance with one embodiment of the present invention;
FIG. 24 shows a close up of the distal portion of FIG. 23, in accordance with one embodiment of the present invention;
FIG. 25 is a view similar to FIG. 24 from another direction showing the ball and socket interface between the spring assembly and the tubular support element, in accordance with one embodiment of the present invention;
FIG. 26 is a view similar to FIGS. 24-25 but from a top and distal end, in accordance with one embodiment of the present invention;
FIG. 27 shows an alternative embodiment where the flexible shaft 20a is a weave of wires forming a stent-like structure that is flexible and also able to transfer torque, in accordance with one embodiment of the present invention;
FIG. 28A shows an isometric view wherein the flexible shaft is made of coiled wires and wherein the spring is connected to the tips, in accordance with one embodiment of the present invention;
FIG. 28B is a fragmentary view broken at line B-B of FIG. 28A showing the volume V of space between the flexible shaft 20a and the spring 30, in accordance with one embodiment, in accordance with one embodiment of the present invention;
FIG. 28C is an end view of the tissue disrupting element taken at section line B-B of FIG. 28A, in accordance with one embodiment of the present invention; and
FIG. 29 shows a sketch of a tissue disrupting element of the kind shown in FIGS. 20-28C but in a deflected configuration, in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
The present invention generally provides a tissue disruption device that may be used to prepare for inserting an implant into a human or animal body, for example in spinal surgery. A preferred embodiment is particularly configured for cutting and grinding intervertebral disc material during discectomy or fusion procedures in the cervical, thoracic and lumbar spine. The device may comprise a deflectable elongated tissue disrupting element rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state. The tissue disrupting element may be rotatably anchored at a distal location and may be deflectable into a curved configuration. A rotary drive configured to rotate the tissue disrupting element around its central axis in the straightened state and in the curved configuration. An elongated element may be wound around and rigidly affixed to the tissue disrupting element. In some embodiments, the elongated element protrudes sufficiently radially from the tissue disrupting element that rotation of the tissue disrupting element generates an axial motion of disrupted tissue. In one preferred embodiment, the tissue disrupting element and/or elongated element comprises wire mesh. The tissue disruption device of the present invention may include, for example, integrally, a support element (see for example FIG. 3A-3B). The device may be positioned, in or on a vertebral body, for example via lateral access to an anterior portion of a spinal disc, or in another manner. The tissue disruption device may be deployed such that a length of the tissue disrupting element of the device spans the length of the disc and such that deflection of the tissue disrupting element into a curved configuration may occur posteriorly along a plane of deflection (for example along an axial plane using anatomical terminology) and a plane of disruption.
Using the device of the present invention in any of the methods of the present invention may cut, grind or otherwise disrupt soft or hard tissue in a human or animal body. The term “disrupting” as used herein refers generically to any process which changes the state or properties of tissue by direct application of mechanical energy, including but not limited to, cutting, scoring, severing, slicing, lacerating, grinding and pulverizing. The tissue disruption technique, method and device of the present invention may be performed on healthy or diseased tissue, whether hard tissue, for example bone, or soft tissue, such as part of an intervertebral disc.
In contrast to prior art tissue disruption devices and methods, in which the disrupting element is rigid, the tissue disrupting element of the tissue disruption device of the present invention may be flexible and deflectable into a curved configuration. In contrast to prior art devices, which either rotate or flex, but not both, the tissue disrupting element of the device of the present invention may both rotate on its central axis and may deflect to a curved configuration. Furthermore, it may do both simultaneously. In further contrast to prior art tissue disruption devices and methods, in which an element on a shaft rotates on the longitudinal axis of the device, the tissue disrupting element of the device of the present invention may rotate on its central axis. In contrast to prior art tissue disruption devices having elements not rigidly affixed to a shaft, the tissue disrupting element and assembly of the present invention may comprise an elongated element that is rigidly affixed to the tissue disrupting element, which may be a flexible shaft. In further contrast to prior art tissue disruption devices, the device of the present invention may have two fixed endpoints for the tissue disrupting element (which may be or include a flexible shaft). As a result, and as a result of the fact that in contrast to certain prior art devices and methods that swing around a tissue disrupting element or a coil thereof, the present device and methods may not throw around a coil or elongated element or tissue disrupting element but rather may configure the elongated element to be rigidly affixed to the tissue disrupting element (which may be or include a flexible shaft) but without preventing the tissue disrupting element from deflecting, the tissue disruption device and methods of the present invention, may provide control, and in preferred embodiments strict control, over the space and volume and location of the disrupted tissue. This may allow the user to be certain of removing all the tissue in the space in which an implant will be put or in the space in which it is desired that the tissue be disrupted. Furthermore, as a result of this control, in contrast to prior art tissue disruption devices, the device and methods of the present invention may allow the user to disrupt only the relevant space where the implant will be put and not the entire volume of the vertebral disc. For example, using the method and device of the present invention, the annulus may be left in place. Furthermore, some of the nucleus may be left in place. This may allow more selective displacement or disruption of tissue than is possible with the prior art devices and methods. In contrast to the prior art, by leaving a residual disc, which for example may be an outer area and may be curved or arced, the user may create an enclosure for the implant. This may assist in guiding insertion of the implant and in addition may minimize or prevent migration of the inserted implant. Furthermore, it may avoid the consequences of the implant subsiding into soft bone tissue since the implant may rest on the hard/cartilaginous tissue that is not removed during disruption. In still further contrast to prior art methods and devices, the devices and methods of the present invention may as a result of its strict control and ability to leave a residue of the disc to remain in place, allow shorter surgical operations that may involve less surgical work. The medical benefits of having shorter surgery are well known—less trauma, faster recuperation, etc. The above-referenced control over and selectivity over the tissue to be disrupted may be achieved in one preferred embodiment by having the tissue disrupting element (and assembly) free to rotate on its own central axis and free to deflect but not free to sway, or in certain other preferred embodiments, also free to sway within defined limits of for example up to 5 degrees from a deflecting plane or up to 10 or up to for example 20 degrees or up to 30 degrees. In still further contrast to prior art devices and methods of tissue disruption, in the present invention, the disrupted tissue may, in certain preferred embodiments, for example where the elongated element is helical, be automatically drawn into and through a conduit and out the body of the patient as a direct automatic result of the rotation of the tissue disrupting element and elongated element without the need for a separate element to take the disrupted tissue out of the body. In contrast to prior art tissue disruption devices and methods, the tissue disruption device and methods of the present invention may result in vibration of a flexible shaft from the simultaneous deflection to the curved configuration and the rotation around its central axis. In contrast to the prior art, moreover, where in some embodiments deflection is all or nothing, the tissue disrupting element may flex gradually to a range of curved configuration until it reaches a fully curved configuration, and this also provides control over the volume and space of the disrupted tissue. In contrast to the prior art, the amount of radial displacement of the tissue disrupting element from the longitudinal axis L (see FIG. 1) during deflection or during an arching motion may be predetermined, for example, based on configuration of the points of attachment of the tissue disrupting element to support element 40. Furthermore, in contrast to the prior art, the volume of disrupted tissue may be predetermined, at least in part, by configuration of the tissue disrupting element, elongated element, support element and/or a relative position between movable pivots or between a movable pivot and a fixed pivot. The volume of disrupted tissue disrupted by device 10 may be predetermined or controlled. For example, it may be predetermined or controlled, at least in part, by a shape of elongated element 30, by a diameter of tissue disrupting element 20, by a length of tissue disrupting element 20 between the movable pivot 44 and the fixed pivot 45 (i.e. by a length of the deflecting portion of tissue disrupting element) and/or by the maximum displacement of an arching motion (at the widest part of the “D”) during deflection to the curved configuration. In contrast to the prior art, wherein a tissue disruptor may be uniform in how it is implemented for soft and hard tissue, the tissue disrupting device and method of the present invention may involve controlling the RPM of the rotary drive (and hence of the tissue disrupting assembly 21) and tailoring the density of the wrappings of the elongated element 30 in order to custom-tailor the tissue disruption for various types of target tissue, i.e. bone, soft tissue.
The principles and operation of an apparatus and method for a deflectable tissue disruption device according to the present invention may be better understood with reference to the drawings and the accompanying description.
As shown in FIG. 1, a distal portion 10A of tissue disruption device 10 may comprise a deflectable elongated tissue disrupting element 20. As seen in FIG. 1, tissue disrupting element 20 may be rotatable around its central axis (the axis is labeled “C”). The central axis C may be parallel to and may in some cases be collinear with the longitudinal axis L of device 10, particularly when the tissue disrupting element 20 is in a straightened state. On the other hand, when tissue disrupting element 20 is in its curved configuration, as shown in FIG. 2A-2B and FIGS. 9B-10B, its central axis C (see broken line in FIG. 2A) would be curved and would neither be collinear with or even parallel to the longitudinal axis L of device 10. The term “distal portion” 10A of tissue disruption device 10 includes the tissue disrupting assembly 21 and at least a distal part of the length of the support element 40, i.e. from a distal end of the support element 40 to some point on the support element that is proximal to the movable pivot 44. Accordingly, the distal portion 10A of the tissue disruption device 10 may include the most distal 10%, or in other preferred embodiments, the most distal 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%, for example, of device 10.
Tissue disrupting element 20 may be rotatably anchored at a distal location, i.e. anchored but still able to rotate while remaining anchored. The distal location may be a distal end of device 10. Accordingly, a distal end of the tissue disrupting device may be rotatably anchored at a distal end of the support element 40. The tissue disrupting element 20 may be anchored to a different portion of device 10 or to a separate device external to device 10. The term “distal location” refers to a location that is distal by reference to the part of device 10 that is normally inserted first into the patient and may normally be controlled by the user. The “proximal” location refers to the location that would normally be inserted into the patient last. Accordingly, the distal part of device 10 would normally be inserted into the patient first. In a preferred embodiment, the distal location is adjacent the distal end of tissue disrupting element 20. In other preferred embodiments where the deflection of the tissue disrupting element is along only part of its length, the distal location may be more proximal than that. In either case, in a preferred embodiment, the distal location is at or adjacent to the most distal part of the tissue disrupting element that deflects to a curved configuration. In other preferred embodiments, the distal location is at least as distal as the most distal part of the tissue disrupting element that deflects to the curved configuration.
A rotary drive 98 is shown in FIGS. 3A-3B but is understood to be broad enough to include any mechanism for rotating tissue disrupting element 20. Rotary drive 98, which may include a rotary drive shaft and a motor in one preferred embodiment, may be configured to rotate the tissue disrupting element 20 around its central axis in the straightened state and in the curved configuration. Accordingly, rotary drive 98 may be configured to transfer rotary power to the tissue disrupting element 20 while accommodating the deflecting motion of tissue disrupting element 20. Typically, the rotary drive would not be the element that deflects tissue disrupting element 20 into its curved configuration, although this is not a limitation or requirement and in a different embodiment a rotary drive both deflects and rotates tissue disrupting element 20. Typically, rather, a separate mechanism may induce the deflection of tissue disrupting element 20 to its curved configuration. In some preferred embodiments, as shown in FIGS. 3A-3B, rotary drive 98 is located at a proximal end or at a proximal portion of device 10.
Most preferably, one or more motors may provide a motive force to drive tissue disrupting element 20. The motors may be electrically, hydraulically or pneumatically driven, with the electric option typically preferred for reasons of convenience of implementation. Manually actuated rotary drive arrangements, for example, with a manually rotated power input handle, also fall within the scope of the present invention.
As shown in FIG. 3A-3B, rotary drive 98 may be located in the proximal portion of the device 10, and may remain outside the body of the human or animal subject during operation of device 10. Rotary drive 98 may be exemplified by a motor. In this case, the output power it transfers along an elongated member by a rotary drive shaft, which must be configured to transfer rotary power to tissue disrupting element 20. Alternatively, the present invention may employ one or more miniature motors deployed in proximity to tissue disrupting element 20, i.e., near the distal end of the device 10. Suitable miniature motors are commercially available from a number of sources, such as the product line “DC-Micromotors” available from Dr. Fritz Faulhaber GmbH (Germany), and rotary SQUIGGLE™ motors available from NewScale Technologies of Victor, N.Y. (USA). The required motor specifications can readily be chosen by one ordinarily skilled in the art according to the power, speed and maximum torque required for each given application. In some cases, a plurality of miniature motors may be connected in series to increase the total output power of the assembly. When in its curved configuration shown in FIG. 2A-2B, 9A-9B, 10A-10B, for example, tissue disrupting element 20 may be connected in a such a way to a rotary drive or other mechanism so as to ensure that tissue disrupting element 20 does not rotate around the longitudinal axis L of device but rather continues to rotate around its own central axis C. The nature of the rotary drive 98, the connection to the rotary drive 98 or any other mechanism ensuring that tissue disrupting element 20 rotates on its own central axis may be anything suitable, which may include, for example (i) a mechanism identical to or similar to the mechanism used for spinning flexible shafts connecting the wheel of a car to the tachometer of the car or (ii) the mechanism used in plumber's snakes for spinning flexible shafts used to clean pipes or sewers, or similar mechanisms. In a preferred position of deployment, the longitudinal axis L of device 10 is parallel to an axis of delivery and to a direction of insertion of device 10.
As shown in FIG. 2A-2B, FIG. 9A and FIG. 10A, in the curved configuration of the deflectable elongated tissue disrupting element 20, the tissue disrupting element 20 may, when combined with longitudinal axis L of device 10, form a “D” shape, or substantially a D-shape. The curved configuration of the tissue disrupting element 20 may also comprise an arch. It should be noted that the tissue disrupting element 20 may continue to rotate on its central axis C during and after the deflection to its curved configuration. In a preferred embodiment, tissue disrupting element 20 (and assembly 21) rotates on its central axis C during the entire deflection from the straightened state to the curved configuration. In some other preferred embodiments, the tissue disrupting element 20 rotates on its central axis C during only the last 90%, or last two-thirds or last half or last third or last quarter of the deflection.
Rotation of tissue disrupting element 20 on its central axis C while the tissue disrupting element 20 deflects into the curved configuration may result in vibration of tissue disrupting element 20. Any such vibration may be greater, the more curved or deflected the tissue disrupting-element is.
Tissue disrupting element 20 may be deflectable into its curved configuration all along its length in one preferred embodiment. In other preferred embodiments, tissue disrupting element 20 may be deflectable into its curved configuration along only a portion of its length, for example along 90%, five-sixths, four-fifths, three-quarters, two-thirds, half, one-third, one-quarter, etc. of its length. Accordingly, the curved configuration of tissue disrupting element 20 may extend from the distal location to a proximal location. The proximal location may lie on longitudinal axis L, although this is not a requirement. The curved configuration may extend from the distal location to a proximal location such that the proximal location is situated in a proximal half (defined to mean the most proximal half of the length) of the tissue disrupting element 20 or along the most proximal 90%, five-sixths, four-fifths, three-quarters, two-thirds, half, one-third, or in other preferred embodiments, along one-quarter, etc. of the length of tissue disrupting element 20. The curved configuration may extend from the distal location to a proximal end (the very end) of the entire tissue disrupting element 20. The proximal end may lie on the longitudinal axis of the device.
Tissue disrupting element 20 may be deflectable into the curved configuration in a number of ways. In one preferred embodiment best appreciated from FIG. 1 and FIG. 2, tissue disrupting element 20 is deflectable by axially moving a movable pivot 44 of a support element 40 toward the distal location. The movable pivot may define a proximal end of the curved configuration of the tissue disrupting element. The movable pivot 44 may be situated at a proximal end (i.e. the very end) of tissue disrupting element 20, or at a proximal portion (located in the most proximal half or third or quarter or fifth of sixth or seventh or tenth of tissue disrupting element 20). The movable pivot 44 may be connected to an end of tissue disrupting element 20. In other preferred embodiments, tissue disrupting element 20 may be deflected into its curved configuration from its straightened state by an actuator element that is not comprised of a movable pivot plus a fixed pivot (fixed in terms of movement in the axial direction). For example, each end of tissue disrupting element 20 may be connected to a movable pivot 44 actuated by an actuator element (not shown). The movable pivots 44 may be part of a support element 40. The actuating element that moves movable pivot 44 may be any suitable element including a pushing element, a magnet, etc. In a preferred embodiment described in connection with FIGS. 20-30, axial compression of a shaft 20a toward a distal fixed pivot may induce the deflection of the tissue disrupting element 20.
As shown in FIG. 3A-3B, support element 40 of device 10 may also include, for example integrated therewith at a proximal end, a deflection handle 85 and a rotary drive 98 for deflecting and rotating tissue disrupting element 20 (and assembly 21). In operation, in one preferred embodiment, an opening in the tissue spanning roughly 40 to 60 millimeters is made by a surgeon to allow room for the length of the tissue disrupting element 20, although this distance is by no means a kind of limitation. In operation, rotation of tissue disrupting element 20 may generate an axial motion of disrupted tissue and may be such as to move the disrupted tissue into and through the support element 40 and out of the body of the subject/patient. Support element 40 may also function as a conduit for disruption tissue. In certain preferred embodiments, support element 40 may also be used as a conduit for transferring anchoring elements or other devices to or adjacent to or near the site where the device 10 is placed, for example on a vertebral body.
As seen from FIG. 1A-1B and FIG. 2A-2B, tissue disrupting element 20 may be deflectable by virtue of being a flexible shaft 20a (or flexible cable). In that case, device 10 may further comprise an elongated element 30 that may be wound around tissue disrupting element 20 and that may be rigidly affixed to tissue disrupting element 20. Elongated element 30 may be rigidly affixed to tissue disrupting element 20 at one or at least one or at least two and preferably at three or four points (or more) along tissue disrupting element 20. Note that although the tissue disrupting element 20 may be rigidly affixed to elongated element 30, tissue disrupting element 20 may nonetheless still be deflectable (i.e. flexible), and in particular sufficiently flexible so as to deflect to its curved configuration, away from the longitudinal axis L. A preferred embodiment of the device 10 and methods of the present invention in which there is a space between the shaft 20a and elongated element 30 is discussed below.
Although in preferred embodiments where tissue disrupting element 20 is deflectable as a result of being flexible, (i.e. embodiments other than those of FIGS. 19A-19C), flexible shaft 20a (see FIG. 13) (and in general tissue disrupting element 20) may have some torsional stiffness, for example sufficient torsional stiffness to assist flexible shaft 20a in rotating around its own central axis C. Elongated element 30 may in fact be tightly wound around the flexible shaft 20a. The density (i.e. windings per inch) of the windings of the elongated element 30 around the tissue disrupting element 20 may vary with the embodiment and may be custom-tailored to the target tissue. This, plus the RPM of the rotary drive, and/or the cross-sectional shape of the element 30, may be utilized to custom-tailor the device 10 and method to particular target tissue types (soft, hard, etc.).
In one preferred embodiment, elongated element 30 itself may have the same torsional rigidity as tissue disrupting element 20, although in other preferred embodiments, elongated element 30 may be somewhat more rigid, although in any case not so rigid as to impede the flexibility of tissue disrupting element 20, and in certain other preferred embodiments the elongated element 30 may be less rigid than the tissue disrupting element 20.
For convenience, the tissue disrupting element 20 plus any elongated element 30 are together referred to as tissue disrupting assembly 21 (FIG. 2A). Although assembly 21 is noted only in FIG. 2A, tissue disrupting element 20 plus elongated element 30 together constitute assembly 21 in any embodiment in which there is an elongated element 30. Assembly 21 may also include the optional clamp/crimp 29 that may sit on tissue disrupting element 20. Hence, the tissue disrupting assembly 21 may be said to be in a straightened state when tissue disrupting element 20 is in a straightened state and may be said to be deflectable to a curved configuration when the tissue disrupting element 20 is deflected to a curved configuration.
In a preferred embodiment shown in FIGS. 1A-5 and FIGS. 9A-10B, elongated element 30 may be wound helically around the tissue disrupting element 20. Elongated element 30 may protrude sufficiently radially from the tissue disrupting element that rotation of the tissue disrupting element 20 generates an axial motion of disrupted tissue.
Elongated element 30 may have various shapes. For example elongated element 30 may have a cylindrical shape in cross-section, may have a square shape in cross-section or may have a triangular shape in cross-section, or may have another shape. Such a triangular shape in cross-section may have two longer sides and wherein the two longer sides project along a radial length of the elongated element 30 outwardly from the flexible shaft. if tissue disrupting element has a rectangular shape in cross-section, in certain preferred embodiments the longer sides of the rectangular shape project radially outward from the flexible shaft. Elongated element 30 may have a thickness that may taper, for example gradually, as the radial length of elongated element 30 from flexible shaft 20a increases.
As shown in FIG. 1A-5 and FIGS. 9B-10A and for example in FIGS. 11 and 13, elongated element 30, by virtue of its shape, may comprise a plurality of cutting edges or blades, that may include a first blade having a first radial length and at least a second blade having a second radial length smaller than the first radial length. The plurality of blades may include blades of differing radial lengths arranged such that an intermediate region along a length of the rotating shaft has blades of a first radial length and regions distal and proximal to the intermediate region have blades of a second radial length smaller than the first radial length.
The amount of radial displacement of the tissue disrupting element 20 from the longitudinal axis L during deflection or during an arching motion may be predetermined, at least in part, based on configuration of the points of attachment of the tissue disrupting element to support element 40. Furthermore, the volume of disrupted tissue may be predetermined, at least in part, by configuration of the tissue disrupting element 20, elongated element 30 and support element 40. In some preferred embodiments, the volume of disrupted tissue is predetermined, at least in part, by configuration of the tissue disrupting element 20, the elongated element 30 and a relative position between movable pivot 44 and a fixed pivot 45 (see FIGS. 1, 2).
The volume of disrupted tissue that is disrupted by device 10 may be predetermined or controlled. For example, it may be predetermined or controlled, at least in part, by a shape of elongated element 30, by a diameter of tissue disrupting element 20, by a length of tissue disrupting element 20 between the movable pivot 44 and the fixed pivot 45 (i.e. by a length of the deflecting portion of tissue disrupting element) and/or by the maximum displacement of an arching motion (at the widest part of the “D”) during deflection to the curved configuration.
In accordance with the present invention, deflection of the tissue disrupting element 20 may be induced by any suitable means that allows continued rotation of tissue disrupting element 20 along its central axis C. However, in addition to the fact of deflection, which may be induced for example by a force exerted against movable pivot 44 toward a fixed pivot 45 of a support element 40, the direction, nature and/or shape of the deflection to the curved configuration, may also be controlled. For example, in one preferred embodiment, the support element 40 comprises a blocking element 42 (3A, 3B, 8A, 9B, 10A) that directs tissue disrupting element 20 to move or deflect to the curved configuration, for example in an arching motion, in a direction along a deflection plane, for example a deflection plane perpendicular to a direction of elongation of the device 10. The deflection plane may be an anatomically axial plane in some preferred embodiments.
As best seen from FIG. 5 and FIG. 10A, blocking element 42 may be a beam having a C-shape in cross-section. The C-shaped beam 42 may direct movement of tissue disrupting element 20 laterally along the plane perpendicular to the direction of elongation of device 10 and parallel to two of the sides of C-shaped beam 42. Typically, depending on the orientation of the device 10 in the subject, this plane perpendicular to the direction of elongation of device 10 may be axial/horizontal in the anatomical sense and it other preferred embodiments it may be vertical (a sagittal plane, a plane parallel to the sagittal plane, a frontal/coronal plane or a plane parallel to the frontal/coronal plane) in the anatomical sense. The C-shaped beam may be a beam that is open (or in various other preferred embodiments, is sufficiently open, or is open along a majority of its length or is open alongside all of or almost all of the length of the tissue disrupting element 20) on one of its four sides so as to allow deflection out of the open side. The blocking element 42 in the form of the C-shaped beam 42 may be at least partially closed OR the other three sides. For example, as best seen in FIGS. 9B and 10A, a C-shaped beam would have its open side on the side that the deflecting tissue disrupting element 20 deflects through. Blocking element 42 may be integrated to the remainder of support element 40 (see FIGS. 3A-3B) and may extend along only a distal portion 10A of device 10 it where tissue disrupting element 20 is located. As shown in FIG. 1A, an elevation 43 or hump 43 on tissue disruption seat 400A is another element that may be used to facilitate movement of tissue disrupting element 20 (and assembly 21) in any embodiment substantially along a plane of deflection, such as shown in FIG. 10A, from the straightened state to the curved configuration. It is noted that this deflection is typically occurring when the element 20 is simultaneously rotating on its central axis C.
In one preferred embodiment, as appreciated from FIGS. 2A-2B, the deflection of the tissue disrupting element 20 occurs when movable pivot 44 of support element 40 moves. For example, deflection of tissue disrupting element 20 may occur when movable pivot 44 moves linearly, for example along a direction of insertion of device 10 into the body, or may occur when movable pivot moves within the C-shaped beam 42 that comprises blocking element 42, as shown in FIGS. 3A-10B. Support element 40 may be attached to tissue disrupting element 20 at movable pivot 44 and may also be attached at one or more fixed pivots 45, as shown in FIG. 2A-2B, 9B, 10A.
As appreciated from FIGS. 1A, 2A, 9B, 10A, a pushing component 400 (which comprise a shaft) of support element 40 may move movable pivot 44, to which a proximal end of tissue disrupting element 20 may be connected, thereby inducing flexion of tissue disrupting element 20 (and assembly 21). Although movable pivot 44 is not visible in FIG. 4, this figure does show the pushing component 400, in contrast to FIG. 5 where it is specifically absent. Tissue disrupting element 20 may be mechanically connected at a universal joint to a shaft that may be situated within pushing component 400 and that may receive rotary motion from rotary drive 98. Movable pivot 44 may be situated at or within a universal joint in order to maintain rotation and still deflect at movable pivot 44. The rotary drive shaft of pushing component 400 may also be a flexible rotary drive shaft that continues past movable pivot 44 as tissue disrupting element 20 in the form of a flexible shaft 20a.
As shown in FIG. 5, certain portions of the length of support element 40, for example at blocking element 42, may in some preferred embodiments have discontinuous or open walls, as necessary to accommodate a wide tissue disrupting assembly 21, which may for example be wide due to the elongated element 30 being wide (or due to the tissue disrupting element 20 being wide).
As shown in FIGS. 3A-3B, pushing component 400 may for example be actuatable by a deflection handle 85 that may be situated at the proximal end of device 10. For example, squeezing handle may induce a movable pivot 44 to advance toward a fixed pivot 45 and induce deflection of tissue disrupting element 20 (and assembly 21) to a curved configuration. This may occur, for example by means of a shaft (not shown) within pushing element 400 that may operatively engage movable pivot 44 to rotary drive 98. Releasing handle 85 may restore tissue disrupting element 20 (and assembly 21) to its straightened state. This mechanism for inducing deflection of tissue disrupting element 20 (and assembly 21) is not meant as a requirement or limiting feature, and other suitable mechanisms may be employed.
In one preferred embodiment, strict control is maintained over the location and volume or disrupted tissue by allowing tissue disrupting element 20 only two degrees of freedom—rotation around or on its own central axis and deflection (or deflectability), for example within or substantially within (plus or minus 5 degrees) a deflection plane perpendicular to a bottom surface 48 (FIG. 10B) of device 10 in embodiments wherein such bottom surface 48 is flat, to its curved configuration of tissue disrupting element 20 (and assembly 21). These freedoms of movement are depicted by arrows in FIG. 1B. The fixed pivot structure 45B around fixed pivot 45, which may include surrounding side walls 46, comprises one way to accomplish this, as seen in FIGS. 1A-1B. Although the restrictive fixed pivot structure 45B that has the side walls 46 is not shown in certain other figures, for example FIGS. 9A and 10B, it should be understood that these other figures could just as well be adapted to show the fixed pivot structure 45B embodiment depicted in FIGS. 1A-1B. Thus, the lower arrow in FIG. 1B indicates rotation around a central axis, C, whereas the upper arrow indicates rotation by “fixed” joint 45 (also called fixed pivot 45) around a separate perpendicular axis labeled “D” since rotation around axis D may permit deflection to the curved configuration. It is noted that fixed joint 45 or fixed pivot 45 is called “fixed” since it does not move linearly, as does movable pivot 44 (visible in FIGS. 2A, 2B), along longitudinal axis L (or central axis C).
In certain other preferred embodiments, the strict control over the location and volume of disrupted tissue from the strict control over the movement of tissue disrupting element 20 (and assembly 21) is generally maintained but a third degree of freedom is introduced so as to either slightly relax such strict control or else to at least permit greater predetermined movement of tissue disrupting element 20 (and of assembly 21). In these embodiments, tissue disrupting element 20 may have three degrees of freedom including rotation around its central axis, deflectability to its curved configuration and swaying away from a plane of deflection (for example a plane perpendicular to a bottom surface of the device that may be flat) to either side of the plane of deflection when the tissue disrupting element is in the curved configuration. The swaying is depicted in FIG. 2B including by the arrow in this figure. Although FIG. 2B shows the swaying to one particular side of a deflection plane, such swaying may also occur to the other side of the deflection plane. The swaying may be due to the rotation and deflection of tissue disrupting element 20 and/or any accompanying vibrations. In a preferred embodiment, due to blocking element 42, the swaying motion may be limited to 5 degrees, and in other preferred embodiments to 10 degrees, or in other preferred embodiments, to 15 degrees or to 25 degrees or to 30 degrees. In a preferred embodiment, the amount of swaying from the deflection plane may be predetermined by the structure of one or more of the fixed pivot 45 and the movable pivot 44 and by the structure of tissue disrupting element 20 (i.e. its thickness or diameter) and blocking element 42. In a preferred embodiment, tissue disrupting assembly 21 sways out of the deflection plane together as one unit. It is understood that the deflection plane referred to is defined to be a plane perpendicular to a flat surface that device 10 may rest on, or perpendicular to a bottom surface 48 (see FIG. 10B) of device 10 that may be flat. As shown in FIGS. 2A-2B, device 10 may include a fixed pivot structure 45A that may be structured to be without complete side walls, thus allowing a pivot ball 45 that may be within fixed pivot structure 45A to move sideways. In contrast, in FIGS. 1A-1B, sideways movement of a fixed pivot ball 45 having a tissue disrupting element 20 attached thereto, may be limited by a fixed pivot structure 45B that may have complete or sufficiently complete side walls 46. It should be understood that the curved configuration shown in FIGS. 2A-2B may also be extrapolated to the embodiment shown in FIGS. 1A-1B and likewise the straightened configuration of FIGS. 1A-1B may be extrapolated to the embodiment shown in FIGS. 2A-2B.
As shown for example in FIGS. 2A-2B, 9A-9B and 10A-10B, in any suitable embodiment, tissue disrupting assembly 21 may include a clamp or crimp 29, for example in the shape of a ring, situated on one or more ends of tissue disrupting element 20 in order to maintain elongated element 30 affixed to tissue disrupting element 20. This clamp/crimp 29 is purely optional and many preferred embodiments may not have this element.
As shown in FIG. 11, in one preferred embodiment, one or more elements of tissue disrupting element 20 and elongated element 30 may comprise a mesh of wires or may be formed of a mesh of wires. The mesh of wires may be a braided mesh of fine wires. In one preferred embodiment shown in FIG. 11 and FIG. 12, each strand of the mesh of wires may be shaped like a helix.
For example, an outer surface 27 of the tissue disrupting element 20 may comprise or be formed of a mesh 92 of wires. Furthermore, as detailed below, the elongated element 30 itself may comprise or be formed of a wire 91 of the wire mesh 92.
In one preferred embodiment of tissue disrupting assembly 21 shown in FIG. 11, the wire mesh 92 may be such that the wires 91 of wire mesh 92 support each other geometrically without having to be affixed to a rigid shaft. In another preferred embodiment shown in FIG. 13, the wire mesh 92 may be fitted over a flexible shaft 20a comprising tissue disrupting element 20.
Wires 91 of wire mesh 92 may be helically wound around the central axis of the device 10, the wires 91 supporting one another without being rigidly connected to one another. As seen in FIG. 11, one (or more) particular wire 91a of the wires 91 (which in this case are helically wound) of wire mesh 92 may have an odd shape relative to the other wires, for example by having a surface that protrudes radially beyond the outer surface and forms a cutting edge for disrupting tissue. Accordingly, as seen in FIG. 11, elongated element 30 of tissue disrupting assembly 21 may comprise the one particular wire 91a, which may be helically shaped. Of course, in other preferred embodiments, the particular wire 91a is not necessarily limited to a single salient wire and may comprise multiple salient wires. Two opposing wires that have the same or different geometric cross-sections may be assembled (with or without being fitted onto a flexible shaft) to form the tissue disrupting element 20 or assembly 21—this may resemble a strand of DNA, for example. FIG. 12 is a side view of a representative section (portion) of wire mesh 92 shown in FIG. 11.
In one preferred embodiment, one of the particular wire 91a, which may be helical, may have a triangular shape in cross-section, or may another shape (such as rectangular). Such a triangular shape in cross-section may have two longer sides and the two longer sides may project along a radial length of the elongated element 30 outwardly from the flexible shaft. Particular wire or wires 91a may have a thickness that may taper, for example gradually, as the radial length of elongated element 30 from flexible shaft 20a increases.
The wire mesh 92 may be fitted over flexible shaft 20a. For example, as shown in FIG. 13, the tissue disrupting element 20 may comprise a cylindrical surface 20a and the mesh of wires may surround all or at least a portion of a length of the cylindrical surface 20a. As also seen in FIG. 13, at least one end 92a (and preferably both ends) of wire mesh 92 (or of a wire of wire mesh 92) may be connected to the cylindrical surface 20a to inhibit axial translation (along shaft 20a) of wires of wire mesh 92 during rotation of the tissue disrupting assembly 21. Accordingly, in a preferred embodiment, whenever the shaft 20a flexes/deflects, wire mesh 92 conforms and flexes equally or equivalently.
The preferred embodiment shown in FIG. 14 depicts wire mesh 92 that is rigid enough to form the tissue disrupting element 20 without having to be fitted onto a separate flexible shaft 20a. Notwithstanding this, wire mesh 92 may be flexible enough to bend and deflect to a curved configuration of tissue disrupting element 20 when actuated to do so.
As shown in FIG. 14, the odd-shaped wire 91a of wire mesh 92 may be cupped-shaped, i.e. curved in a direction so that axial rotation of device 10 or of tissue disrupting assembly 21 pulls disrupted tissue into a center of wire mesh 92. For example, wire 91a may have a curved-U-shape in cross-section.
As noted, tissue disrupting element 20 may be deflectable by virtue of being a flexible shaft 20a (or flexible cable). In certain preferred embodiments, tissue disrupting element 20 may instead, or in addition, be deflectable by virtue of other structural characteristics, such as tissue disrupting element 20 being segmented, as shown in FIGS. 18A, 18B, 19A, 193, and 19C. Specifically, FIGS. 18A and 18B, whose segmented embodiment may be incorporated into any suitable embodiment described or depicted in this patent application, illustrate a tissue disrupting element 20 comprising a rotating shaft 146 subdivided into three segments 146a-146c interconnected by flexible drive linkages 166. The end of distal segment 146c may be pivotally anchored at a hinge 68 while being still free to rotate about its longitudinal axis. Similarly, the proximal end of proximal segment 146a may be pivotally anchored by a pin-in-slot arrangement 70 while being free to rotate about its longitudinal axis. When rotary pushing element 400 (see FIG. 1A), which may be or contain a drive shaft, is advanced, a pin-in-slot arrangement 70 may allow the tissue disrupting element 20 to transform from the state of FIG. 18A to that of FIG. 18B, performing an arching motion of the segments, and sweeping through what may be a D-shaped volume of tissue. FIGS. 19A-19C illustrate a further embodiment similar to FIGS. 18A-18B except that the segments here are all mounted on a common flexible shaft 72. Where tissue disrupting element 20 is segmented, as in the embodiments of FIGS. 18A-19C, an individual elongated element 30 (not shown in FIGS. 18A-19C) as described herein may be wound around each individual segment (for example 146a-146c) of tissue disrupting element 20.
As shown in FIG. 15, the present invention may also be described as a method 100 of disrupting target tissue in a human or animal body. Method 100 may comprise a step 110 of rotatably anchoring at a distal location a deflectable elongated tissue disrupting element 20 to a support element 40, the tissue disrupting element 20 rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state. The structural elements mentioned in step 110 may conform to any of the apparatus embodiments described herein. Method 100 may also have a step 120 of introducing the deflectable (for example flexible or segmented) elongated tissue disrupting element 20 and support element 40 into the body of the patient or subject. A further step 130 of method 100 may be deflecting the tissue disrupting element into a curved configuration while rotating the tissue disrupting element around its central axis, so as to disrupt target tissue.
Method 100 may include a step of the tissue disrupting element rotating at a plurality of arching positions. In some versions, method 100 may include a step of introducing a rigid conduit into the body adjacent the target tissue and introducing through the rigid conduit the tissue disrupting device. There may also be a step of method 100 comprising using a support element to move the tissue disrupting element in an arching motion while the tissue disrupting element is rotating.
Some versions of method 100 include a step of axially moving a movable pivot attached to the tissue disrupting element. Method 100 may also comprise using a blocking element to direct the tissue disrupting element to deflect to the curved configuration in a direction along a plane perpendicular to a direction of elongation of the device. The blocking element may have a C-shaped cross-section to direct the tissue disrupting element. A step of method 100 may be pivoting the tissue disrupting element at a proximal location so that the curved configuration of the tissue disrupting element extends from the distal location to the proximal location. A step of method 100 may also be using a C-shaped support element to guide the arching motion in an anterior direction.
Method 100 may also involve using an elongated element, for example a helically wound elongated element 30, to draw disrupted tissue back through a conduit through which the tissue disrupting element 20 was delivered. Method 100 may utilize an Archimedes-type screw, for example as seen in FIG. 3. An elongated element rigidly affixed to and wound around the tissue disrupting element may be used as a cutting edge to disrupt the target tissue, which may then be drawn back through the conduit for example.
In some versions of method 100, a step may be configuring the tissue disrupting element to comprise a mesh of wires such that the wires support one another without being rigidly connected to one another. Any of the structural details described regarding device 10 may be used to implement method 100, including the structural details involving wire or wires 91 of wire mesh 92.
As shown in FIG. 16, the present invention may also be described as a method 200 of disrupting tissue of an intervertebral disc of a human or animal body. Method 200 may comprise a step 210 of introducing into the human or animal body a deflectable (for example, flexible or segmented) elongated tissue disrupting element, for example as part of a tissue disruption device 10, the tissue disrupting element rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state, the tissue disrupting element anchored at a distal location. The structural elements mentioned in step 210 may conform to any of the apparatus embodiments described herein. The tissue disrupting element introduced may be introduced laterally and may be situated so as to span a vertebral body, as shown in FIGS. 6-9B. For example, the tissue disrupting element of a tissue disruption device 10 may be introduced in an anterior portion of the vertebral body and deflected posteriorly to disrupt tissue, for example target tissue in the nucleus of the vertebral body.
Method 200 may also have a step 220 of deflecting the tissue disrupting element into a curved configuration while the tissue disrupting element is rotating around its central axis and anchored at the distal location, in order to disrupt a volume of tissue within a space occupied by the intervertebral disc while leaving (i.e. undisturbed) at least an arcuate volume of tissue of the intervertebral disc. Method 200 may involve leaving (i.e. undisturbed) the arcuate volume of (i.e. undisturbed) tissue such that the at least an arcuate volume of (i.e. undisturbed) tissue lies on a plane that the intervertebral disc lies in. For example, the step 220 of method 200 may leave (i.e. undisturbed) all of the annulus of the vertebral body plus some (5% or 10% or 20% or 30% or 40% or 50% or ⅔ or ⅘ or 90% in various alternative preferred embodiments) of the nucleus of the vertebral body in a preferred embodiment. A step of method 100 may involve leaving (i.e. undisturbed) the at least an arcuate volume of tissue such that the at least an arcuate volume of tissue separates the implant from spinal canal tissue (or in other preferred embodiments spinal cord tissue) in the human or animal body.
A further step 230 of method 200 may be implanting the implant so that the implant is enclosed by the at least arcuate volume of (i.e. undisturbed) tissue of the intervertebral disc.
As seen in FIG. 17, the present invention may further be described as a method 300 of disrupting tissue of an intervertebral disc of a human or animal body. Method 300 may have a step 310 of introducing into the human or animal body a deflectable elongated tissue disrupting element rotatable around its central axis, the central axis being a longitudinal axis when the disrupting element is in a straightened state, the tissue disrupting element anchored at a distal location, the tissue disrupting element having an elongated element rigidly and helically wound around the flexible shaft. The structural elements mentioned in step 310 may conform to any of the apparatus embodiments described herein.
Another step 320 of method 300 may be predefining a volume and location of tissue for disruption by configuring a support element attached to the tissue disrupting element. Method 300 may also include a step 330 of deflecting the tissue disrupting element into a curved configuration while the tissue disrupting element is rotating, in order to disrupt a volume of tissue within a space occupied by the intervertebral disc while leaving (i.e. undisturbed) at least an arcuate volume of tissue of the intervertebral disc.
Some versions of method 300 may involve configuring the support element by setting a relative position of a movable pivot and a fixed pivot that are attached to the tissue disrupting element. Other versions of method 300 may involve configuring the support element by setting a relative position of two or more movable pivots that are attached to the tissue disrupting element.
Method 300 may also involve further predefining the volume and location of the tissue for disruption by setting a diameter of the tissue disrupting element and by setting a shape of an elongated element fixedly attached to and wound around the tissue disrupting element. Other versions of method 300 may involve predefining the volume and location of the tissue for disruption by setting a diameter of the tissue disrupting element and by setting a shape of an elongated element fixedly attached to and wound around the tissue disrupting element. Some versions of method 300 may involve controlling or predetermining the volume of disrupted tissue disrupted by device 10, at least in part, by a shape of elongated element 30, by a diameter of tissue disrupting element 20, by a length of tissue disrupting element 20 between the movable pivot 44 and the fixed pivot 45 (i.e. by a length of the deflecting portion of tissue disrupting element) and/or by the maximum displacement of an arching motion (at the widest part of the “D”) during deflection to the curved configuration.
It should be understood that one or more steps of the methods 100, 200, 300 described herein may be combined. Furthermore, any suitable embodiment of device 10 described herein consistent with the steps of a particular method may be used in any such method 100, 200, 300.
“Rotation” of the tissue disrupting element around its central axis should be understood to be broad enough to include rotation in one clockwise direction, rotation in the opposite (counterclockwise) direction and reciprocating rotary motion (i.e. alternating rotation in opposite (i.e. clockwise and counterclockwise) directions).
A deviation of 10% from a magnitude of, for example ten, means between nine and eleven.
It should be understood that wherever a shaft 20 is employed as part of or as the tissue disrupting element 20 by the present invention, a cable may be used. The cable is understood to refer to a rope or other flexible tension member made of twisted strands, for example of wire.
FIGS. 20-29 depict a further preferred embodiment of the device 10 of the present invention, which device may also be used in any suitable method of the present invention (100, 200, 300). In this further preferred embodiment, tissue disruption device 10 may comprise a deflectable elongated tissue disruptor 22 rotatable around its central axis, the central axis being a longitudinal axis when the tissue disruptor 22 is in a straightened state. Tissue disruptor 22 may be rotatably anchored at a distal location and deflectable into a curved configuration. The tissue disruptor 22 may include a helical element 30 that may define a volume of space that is located radially inward of the helical element 30, for accumulation of disrupted tissue. Device 10 may also comprise a rotary drive 98 configured to rotate the tissue disruptor 22 around its (the tissue disruptor's) central axis in the straightened state and in the curved configuration. Other structural features shown in FIGS. 1-19 may also be incorporated into this further embodiment shown in FIGS. 20-29. As one example, a movable pivot 44 (see FIG. 2B) may be used to induce deflection of tissue disruptor 22 and together with other structural features described with respect to previous preferred embodiments, may afford the tissue disruptor three degrees of freedom.
In embodiments shown in FIGS. 20-29, the deflectable elongated tissue disruptor 22, in its broadest form, may be any one of (i) tissue disrupting assembly 21 comprising the flexible shaft 20a and the helical element 30, (ii) flexible shaft 20a without helical element 30, and (iii) helical element 30 without flexible shaft 20a.
Helical element 30 may be shaped as a cylindrical helix or generally cylindrical helix (rather than as a conical helix or generally conical helix). As shown in FIGS. 20-29, helical element 30 may be a helical spring. In one version not shown in the drawings, no shaft is present inward of the helical spring. The drawings (FIGS. 20-29) show the preferred version in which the tissue disruptor 22 may also include a shaft 20a, which may be a flexible shaft 20a, positioned radially inward of the helical element 30, the flexible shaft 20a of the tissue disruptor 22 being rotatably anchored at the distal location. The helical element 30 may be rigidly affixed to the flexible shaft 20a at one or at least one or preferably at two points, or at least two points (or more) along tissue disruptor 22. As in other embodiments, although the tissue disruptor 22 may be rigidly affixed to elongated element 30, tissue disruptor 22 may nonetheless still be deflectable (i.e. flexible), and in particular sufficiently flexible so as to deflect to its curved configuration, away from the longitudinal axis L. Accordingly, as shown in FIG. 29, in the curved configuration of the tissue disruptor 22, the flexible shaft 20a and helical element 30 are each deflected.
As can be appreciated from FIGS. 20-29, affixation (which may be a rigid affixation) of the helical element 30 to flexible shaft 20a may define one or more longitudinal/axial ends of the volume of space. FIGS. 20-29 also show that tissue disruptor 22 may include helical element 30 that may define a volume V of space radially inward of the helical element 30 for accumulation of disrupted tissue. The volume V of space may be such that shaft 20a is surrounded by the volume V of space that is radially inward of the helical element. In a preferred embodiment, such as those shown in FIGS. 20-29, the helical element may be rigidly affixed to a shaft of the tissue disruptor so as to define the volume V of space radially inward of the helical element 30 such that the shaft is centered within the volume V of space.
The volume V of space may extend along at least a majority of (or in other preferred embodiments at least three-quarters of) a length of the tissue disruptor 22 or, in a preferred embodiment, may extend along an entire length of the tissue disruptor 22. In embodiments in which the volume V of space does not extend along the entire length of the tissue disruptor, spring 30 may be shorter than tissue disruptor 22. Alternatively, spring 30 may begin to snugly wrap the flexible shaft 20a at some point along the length of tissue disruptor 22, thus creating a hybrid of, for example, the embodiment shown in any of FIGS. 1-10 with the embodiment shown in FIGS. 20-29.
Tissue disruptor 22 may be rotatably anchored at a distal location to a support element 40 or to a rotary drive 98. For example, the distal location may be a distal end of a support element 40 of the device 10. Accordingly, a distal end of the tissue disrupting device may be rotatably anchored at a distal end of a support element 40.
FIG. 20 shows an isometric view of an assembly 21 of a helical spring connected to a shaft 20a. In the embodiment of FIGS. 20-26, shaft 20a may be a generally solid material. FIG. 21 shows an enlarged view of the tip of FIG. 20 showing a pivot ball 45 (which pivot ball may be fixed in the axial direction) which may interface with a socket to form a joint. Spring 30 may have a greater diameter than the flexible shaft 20a to which it is connected to at end connectors 66, 66′. In particular, the inner diameter of helical element 30, for example spring 30, may be larger than an outer diameter of flexible shaft 20a. The volume V of space may occupy the area defined by the difference in these diameters along the length of the volume V of space. This does not preclude disrupted tissue from also accumulating in the area that is both between the coils and is between the outer and inner diameters of the spring. As shown in FIG. 21, in one version a flexible joint 4 may connect the spring assembly 21 to a rigid shaft 14 (not to be confused with shaft 20a that may form part of the tissue disruptor 22) that may fit inside a support element and may be connected to a rotary drive 98 or to a motor. In this case, axial compression of tissue disruptor 22 may induce deflection of spring 30 and flexible shaft 20a. In other versions, an axially movable proximal pivot may be used to cause deflection while allowing two further degrees of freedom (rotation on central axis and swaying). Thus, the pivots used in FIG. 2B may be incorporated into the embodiments of FIGS. 20-29 to provide the tissue disruptor 22 with a third degree of freedom (swaying), beyond the two degrees of freedom (rotation on the central axis and deflection) readily apparent from the arrows shown in FIG. 21.
FIG. 23 shows an isometric view of the device where the assembly 21 in FIG. 20 is inside a support element 40 and wherein the fixed pivot ball 45 is positioned in a socket (not visible) on the inside of the tip 8. The support element 40, which is shown to be tubular in FIGS. 23-26, is also shown connected to a handle 85. FIG. 24 shows a close up of the distal portion or tip shown in FIG. 23. It shows a slot 999 designed to enable the spring 30 on flexible shaft 20a to be able to flex or deflect outward without being obstructed by the tubular support element 40. FIG. 25 is a view similar to FIG. 24 from another direction showing the ball and socket interface 123 between the spring assembly and the tubular support element. FIG. 26 shows the position of the flexible shaft 20a inside a tubular support element 40.
FIGS. 27-28C depict a version in which a mesh of wires is used to form a shaft of the tissue disruptor 22, as in the embodiments shown in FIGS. 11-14. For example, in FIG. 27 the flexible shaft 20a may be a weave of wires forming a stent-like structure that is flexible and also able to transfer torque. FIG. 27 shows a helical element 30, namely a spring 30, connected to flexible shaft 20a at the tips of the tissue disruptor 22. Spring 30 may be round, square, triangular or of another shape in cross section. FIG. 28A depicts a version in which the flexible shaft 20a is a coiled wire (rather than a stent-like weave of strands). FIG. 28B is a fragmentary view broken at line B-B of FIG. 28A showing the volume V of space between the shaft and the spring. Note that in the embodiments of FIGS. 20-29 spring 30 and flexible shaft 20a may have different pitches from one another, as well as different shapes and/or diameters relative to one another. FIG. 28C is an end view. FIG. 29 is sketch showing a tissue disruptor 22 of any of the embodiments shown in FIGS. 20-28C.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. Therefore, the claimed invention as recited in the claims that follow is not limited to the embodiments described herein.
Patent Application
20140074096
