# Patent

## Title
Powered tissue modification devices and methods

## Abstract

A device for modifying tissue in a spine may include: a shaft having a proximal portion and a distal portion, the distal portion having dimensions which allow it to be passed into an epidural space of the spine and between target and non-target tissues; at least one distal force application member extending from the distal portion of the shaft and configured to facilitate application of at least one of anchoring force and tensioning force to the shaft; at least one movable tissue modifying member coupled with the shaft at or near its distal portion; at least one drive member coupled with the at least one tissue modifying member to activate the at least one tissue modifying member; and at least one power transmission member coupled with the at least one drive member to deliver power to the at least one drive member.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation-in-part of U.S. patent application Ser. No. 11/375,265, entitled “Methods and Apparatus for Tissue Modification,” filed on Mar. 13, 2006, the entire disclosure of which is hereby incorporated by reference, which is a continuation-in-part of PCT Patent Application No. PCT/US2005/037136, filed Oct. 15, 2005, which claimed the benefit of: U.S. Provisional Patent Application No. 60/619,306, filed on Oct. 15, 2004; U.S. Provisional Patent Application No. 60/622,865, filed on Oct. 28, 2004; U.S. Provisional Patent Application No. 60/681,719, filed on May 16, 2005; U.S. Provisional Patent Application No. 60/681,864, filed on May 16, 2005; and U.S. Provisional Patent Application No. 60/685,190, filed on May 27, 2005, PCT Patent Application Pub. No. PCT/US2005/037136, which was incorporated fully by reference in the above-referenced U.S. patent application Ser. No. 11/375,265, is also incorporated fully by reference herein.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods and apparatus for modifying tissue in a patient.
Many pathological conditions in the human body may be caused by enlargement, movement, displacement and/or a variety of other changes of bodily tissue, causing the tissue to press against (or “impinge on”) one or more otherwise normal tissues or organs. For example, a cancerous tumor may press against an adjacent organ and adversely affect the functioning and/or the health of that organ. In other cases, bony growths (or “bone spurs”), arthritic changes in bone and/or soft tissue, redundant soft tissue, or other hypertrophic bone or soft tissue conditions may impinge on nearby nerve and/or vascular tissues and compromise functioning of one or more nerves, reduce blood flow through a blood vessel, or both. Other examples of tissues which may grow or move to press against adjacent tissues include ligaments, tendons, cysts, cartilage, scar tissue, blood vessels, adipose tissue, tumor, hematoma, and inflammatory tissue.
One specific example of a condition caused by tissue impingement is spinal stenosis. Spinal stenosis occurs when neural tissue and/or vascular tissue in the spine become impinged by one or more structures pressing against them (“neural and/or neurovascular impingement”), causing one or more symptoms. This impingement of tissue may occur in one or more of several different areas in the spine, such as in the central spinal canal (the vertical passage through which the spinal cord and cauda equina extends), the lateral recesses of the spinal canal, or one or more intervertebral foramina (the openings through which nerve roots branching from the spinal cord pass).
For explanatory purposes, FIG. 1 is offered to show an approximate top view of a vertebra (one of the bones of the spinal column) with the cauda equina (the horsetail-shaped bundle of nerves that extends from the base of the spinal cord through the central spinal canal) shown in cross section and two nerve roots exiting the central spinal canal and extending through intervertebral foramina on either side of the vertebra. (FIG. 1 is not drawn to exact scale and is intended for exemplary purposes only. It should be emphasized here that the drawing figures appended to this application are not intended to be precisely anatomically correct and are provided for exemplary purposes to facilitate description.) The spinal cord and cauda equina run vertically along the spine through the central spinal canal, while nerve roots branch off of the spinal cord and cauda equina between adjacent vertebrae and extend through the intervertebral foramina.
One common cause of spinal stenosis is buckling and thickening of the ligamentum flavum (one of the ligaments attached to and connecting the vertebrae), as shown in FIG. 1. Buckling or thickening of the ligamentum flavum may impinge on one or more neurovascular structures, dorsal root ganglia, nerve roots and/or the spinal cord itself. Another common cause of neural and neurovascular compression within the spine is disease of one or more of the intervertebral discs (the malleable discs between adjacent vertebrae), which may lead to collapse, bulging or herniation of the disc. In FIG. 1, an intervertebral disc is shown with three solid-tipped arrows demonstrating how the disc might bulge or herniate into the central spinal canal to impinge upon the spinal cord, cauda equina and/or individual nerve roots. Other causes of neural and neurovascular impingement in the spine include: hypertrophy of one or more facet joints (also known as zygopophaseal joints, facet joints provide articulation between adjacent vertebrae—two vertebral facet superior articular processes are shown in FIG. 1); formation of osteophytes (bony growths or “bone spurs”) on vertebrae; spondylolisthesis (sliding of one vertebra relative to an adjacent vertebra); and (facet joint) synovial cysts. Disc, bone, ligament or other tissue may impinge on the spinal cord, the cauda equina, branching spinal nerves and/or blood vessels in the spine to cause loss of function, ischemia (shortage of blood supply) and even permanent damage of neural or neurovascular tissue. In a patient, this may manifest as pain, impaired sensation and/or loss of strength or mobility.
In the United States, spinal stenosis occurs with an incidence of between 4% and 6% of adults aged 50 and older and is the most frequent reason cited for back surgery in patients aged 60 and older. Conservative approaches to the treatment of symptoms of spinal stensosis include systemic medications and physical therapy. Epidural steroid injections may also be utilized, but they do not provide long lasting benefits. When these approaches are inadequate, current treatment for spinal stenosis is generally limited to invasive surgical procedures to remove vertebral ligament, cartilage, bone spurs, synovial cysts, cartilage, and bone to provide increased room for neural and neurovascular tissue. The standard surgical procedure for spinal stenosis treatment includes laminectomy (complete removal of the lamina (see FIG. 1) of one or more vertebrae) or laminotomy (partial removal of the lamina), followed by removal (or “resection”) of the ligamentum flavum. In addition, the surgery often includes partial or occasionally complete facetectomy (removal of all or part of one or more facet joints between vertebrae). In cases where a bulging intervertebral disc contributes to neural impingement, disc material may be removed surgically in a discectomy procedure.
Removal of vertebral bone, as occurs in laminectomy and facetectomy, often leaves the effected area of the spine very unstable, leading to a need for an additional highly invasive fusion procedure that puts extra demands on the patient's vertebrae and limits the patient's ability to move. In a spinal fusion procedure, the vertebrae are attached together with some kind of support mechanism to prevent them from moving relative to one another and to allow adjacent vertebral bones to fuse together. Unfortunately, a surgical spine fusion results in a loss of ability to move the fused section of the back, diminishing the patient's range of motion and causing stress on the discs and facet joints of adjacent vertebral segments.
While laminectomy, facetectomy, discectomy, and spinal fusion frequently improve symptoms of neural and neurovascular impingement in the short term, these procedures are highly invasive, diminish spinal function, drastically disrupt normal anatomy, and increase long-term morbidity above levels seen in untreated patients.
Therefore, it would be desirable to have less invasive methods and devices for addressing neural and neurovascular impingement in a spine. Ideally, methods and devices for addressing impingement in spine would treat one or more targets tissues while preventing unwanted effects on adjacent or nearby non-target tissues. Also ideally, such methods and devices would be minimally invasive and reduce impingement without removing significant amounts of vertebral bone, joint, or other spinal support structures, thereby avoiding the need for spinal fusion and, ideally, reducing the long-term morbidity levels resulting from currently available surgical treatments. It may also be advantageous to have less invasive methods and devices for modifying target tissues in parts of the body other than the spine while preventing modification of non-target tissues. At least some of these objectives will be met by the present invention.
2. Description of Background Art
Flexible wire saws and chain saws, such as threadwire saws (T-saws) and Gigli saws, have been used since the late 1800s to saw through or file/abrade bone and other tissue in the human body. See, for example, Brunori A et al., “Celebrating the Centennial (1894-1994): Leonardo Gigli and H is Wire Saw,” J Neurosurg 82:1086-1090, 1995. An example of one such saw is described in U.S. Pat. No. 8,250, issued to P. A. Stohlmann on Nov. 28, 1876. A description of using a T-saw to cut vertebral bone is provided in Kawahara N et al., “Recapping T-Saw Laminoplasty for Spinal Cord Tumors,” SPINE Volume 24, Number 13, pp. 1363-1370.
A method and apparatus for treating spinal stenosis is described in PCT Patent Application Pub. No. WO 01/08571. A surgical instrument for removing cartilage from a knee cavity is described in U.S. Pat. No. 3,835,859.
SUMMARY OF THE INVENTION
In various embodiments, the present invention provides methods, apparatus and systems for modifying tissue in a patient. Generally, the methods, apparatus and systems may involve using an elongate, at least partially flexible tissue modification device having one or more tissue modifying members to modify one or more target tissues. The tissue modification device may be configured such that when the tissue modification member (or members) is in a position for modifying target tissue, one or more sides, surfaces or portions of the tissue modification device configured to avoid or prevent damage to non-target tissue will face non-target tissue. In various embodiments, during a tissue modification procedure, an anchoring force may be applied at or near either a distal portion or a proximal portion of the tissue modification device, either inside or outside the patient. Pulling or tensioning force may also be applied to the unanchored end of the device to urge the tissue modifying member(s) against target tissue. The tissue modifying members may then be activated to modify tissue while being prevented from extending significantly beyond the target tissue in a proximal or distal direction. In some embodiments, the tissue modifying members may be generally disposed along a length of the tissue modification device that approximates a length of target tissue to be modified.
By “applying an anchoring force,” it is meant that a force is applied to maintain a portion of a device, or the device as a whole, substantially stable or motion-free. Applying an anchoring force is, therefore, not limited to preventing all movement of a device, and in fact, a device to which an anchoring force is applied may actually move in one or more directions in some embodiments. In other embodiments, an anchoring force is applied to maintain a portion of a device substantially stable, while another portion of the device is allowed to move more freely. As will be described in further detail below, applying an anchoring force in one embodiment involves a user of a device grasping the device at or near one of its ends. In other embodiments, devices may use one or more anchoring members to apply an anchoring force. In a number of embodiments, an anchoring force may be applied with or against one or more tissues of a patient's body, and the tissue(s) may often move even as they apply (or help apply) the force. Thus, again, applying an anchoring force to a device does not necessarily mean that all motion of the device is eliminated. Of course, in some embodiments, it may be possible and desirable to eliminate all movement or substantially all movement of a device (or portion of a device), and in some embodiments anchoring force may be used to do so.
Methods, apparatus and systems of aspects of the present invention generally provide for tissue modification while preventing unwanted modification of, or damage to, surrounding tissues. Tensioning the tissue modification device by applying anchoring force at or near one end and applying tensioning or pulling force at or near the opposite end may enhance the ability of tissue modification members of the device to work effectively within a limited treatment space. Applying tensioning force to a predominantly flexible device may also allow the device to have a relatively small profile, thus facilitating its use in less invasive procedures and in other procedures in which alternative approaches to target tissue may be advantageous.
In some embodiments, the described methods, apparatus and systems may be used to modify tissue in a spine, such as for treating neural impingement, neurovascular impingement and/or spinal stenosis. In alternative embodiments, target tissues in other parts of the body may be modified.
In one aspect of the present invention, a device for modifying tissue in a spine may include one or more of the following: a shaft having a proximal portion and a distal portion, the distal portion having dimensions which allow it to be passed into an epidural space of the spine and between target and non-target tissues; at least one distal force application member extending from the distal portion of the shaft and configured to facilitate application of at least one of anchoring force and tensioning force to the shaft; at least one movable tissue modifying member coupled with the shaft at or near its distal portion; at least one drive member coupled with the at least one tissue modifying member to activate the at least one tissue modifying member; and at least one power transmission member coupled with the at least one drive member to deliver power to the at least one drive member.
In another aspect of the present invention, a device for modifying tissue in a patient may include: an elongate, at least partially flexible body having a proximal portion and a distal portion, the distal portion having dimensions which allow it to be passed between target and non-target tissues in the patient; at least one distal force application member extending from the distal portion of the elongate body and configured to facilitate application of at least one of anchoring force and tensioning force to the elongate body; at least one proximal force application member coupled with the elongate body at or near the proximal portion and configured to facilitate application of tensioning force to the elongate body; at least one movable tissue modifying member coupled with the elongate body; at least one drive member coupled with the at least one tissue modifying member to activate the at least one tissue modifying member; and at least one power transmission member coupled with the at least one drive member to deliver power to the at least one drive member.
In another aspect of the present invention, a method for modifying tissue in a spine may include one or more of the following steps: passing a distal portion of a tissue modification device into an epidural space of a spine and between one or more target tissues and one or more non-target tissues; positioning at least one tissue modifying member of the tissue modification device adjacent the target tissue such that the tissue modifying member(s) face the target tissue and do not face the non-target tissue; applying at least one of anchoring force and tensioning force at or near the distal portion and at or near a proximal portion of the tissue modification device to urge the at least one tissue modifying member against the target tissue; and transmitting power to at least one drive member coupled with the at least one tissue modifying member to activate the tissue modifying member(s) and thus modify the target tissue.
These and other aspects and embodiments are described more fully below in the Detailed Description, with reference to the attached Drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is cross-sectional view of a spine, showing a top view of a lumbar vertebra, a cross-sectional view of the cauda equina, and two exiting nerve roots;
FIG. 2 is a cross-sectional view of a portion of a patient's back and spine, showing part of a vertebra and apparatus in place for modifying tissue according to one embodiment of the present invention;
FIG. 3A is a perspective view of a tissue modification device according to one embodiment of the present invention;
FIG. 3B is a perspective view of a portion of the tissue modification device of FIG. 3A;
FIG. 3C is a top view of the portion shown in FIG. 3B;
FIG. 3D is a side view of the portion shown in FIGS. 3B and 3C;
FIGS. 3E and 3F are cross-sectional views of a portion of the tissue modification device taken through lines A-A and B-B, respectively, shown in FIG. 3C;
FIG. 3G is a perspective view of a portion of the tissue modification device of FIGS. 3B-3F, shown with a blade of the device in a closed position according to one embodiment of the present invention;
FIG. 3H is a top view of the portion shown in FIG. 3G;
FIG. 3I is a side view of the portion shown in FIGS. 3G and 3H;
FIG. 4A is a perspective view of a tissue modification device according to one embodiment of the present invention;
FIG. 4B is a perspective view of a portion of the tissue modification device of FIG. 4A;
FIG. 4C is a close-up, perspective view of a portion of the tissue modification device of FIGS. 4A and 4B, showing a tissue modifying member according to one embodiment of the present invention;
FIGS. 5A-5D are cross-sectional views of a spine and demonstrate a methods for using a tissue modification device according to one embodiment of the present invention;
FIG. 6A is a cross-sectional view of a portion of a patient's spine and back, with apparatus for modifying tissue in position for modifying spinal tissue and with a distal portion of the apparatus anchored outside the patient according to one embodiment of the present invention;
FIG. 6B is a cross-sectional view of a portion of a patient's spine and back, with apparatus for modifying tissue in position for modifying spinal tissue and with a distal portion of the apparatus anchored inside the patient according to one embodiment of the present invention;
FIGS. 7A-7S are cross-sectional views of a portion of a patient's spine and back, demonstrating a method for introducing apparatus for modifying spinal tissue to an area in the spine for performing the tissue modification according to one embodiment of the present invention;
FIGS. 8A-8F are cross-sectional views of a portion of a patient's spine and back, demonstrating a method for introducing apparatus for modifying spinal tissue to an area in the spine for performing the tissue modification according to an alternative embodiment of the present invention;
FIGS. 9A-9B are cross-sectional views of a portion of a patient's spine and back, demonstrating a method for introducing apparatus for modifying spinal tissue to an area in the spine for performing the tissue modification according to an alternative embodiment of the present invention;
FIG. 10A is a perspective view of a distal portion of an introducer sheath according to one embodiment of the present invention;
FIGS. 10B and 10C are perspective and cross-sectional views, respectively, of a tissue shield device according to one embodiment of the present invention; and
FIGS. 10D and 10E are perspective and cross-sectional views, respectively, of a tissue shield device according to an alternative embodiment of the present invention.
FIGS. 11A and 11B are cross-sectional views of a spine with a tissue modification device in position for modifying tissue according to various embodiments of the present invention.
FIG. 12 is a cross-sectional view of a portion of a spine with a tissue modification device in position for modifying tissue according to an alternative embodiment of the present invention.
FIGS. 13A-13E are cross-sectional views of a portion of a spine with a tissue modification device in position for modifying tissue according to various alternative embodiments of the present invention.
FIGS. 13F and 13G are cross-sectional views of a portion of the tissue modification device of FIG. 13E, through line C-C on FIG. 13E, in various configurations according to one embodiment of the present invention.
FIG. 14 is a cross-sectional view of a portion of a spine with a tissue modification device having a steerable distal portion in position for modifying tissue according to one embodiment of the present invention.
FIG. 15A is a cross-sectional view of a portion of a spine with a tissue modification device in position for modifying tissue according to one embodiment of the present invention.
FIG. 15B is a close-up of portion D-D of FIG. 15A.
FIG. 16 is a cross-sectional view of a portion of a spine with a tissue modification device in position for modifying tissue according to one embodiment of the present invention.
FIGS. 17A-17E are cross-sectional views taken through line A-A of FIG. 16 according to various alternative embodiments of the present invention.
FIG. 18 is a cross-sectional view taken through line B-B of FIG. 16 according to one embodiment of the present invention.
FIGS. 19-33 are perspective or side views of a distal portion of a tissue modification device according to various alternative embodiments of the present invention.
FIGS. 34A and 34B are perspective views of a distal portion of a tissue modification device according to alternative embodiments of the present invention.
FIGS. 35A and 35B are side views of a distal portion of a tissue modification device according to one embodiment of the present invention.
FIGS. 36A and 36B are side views of a distal portion of a tissue modification device according to an alternative embodiment of the present invention.
FIGS. 37A and 37B are perspective views of a distal portion of a tissue modification device according to an alternative embodiment of the present invention.
FIGS. 38A-38C are end-on views of a distal portion of a tissue modification device according to various alternative embodiments of the present invention.
FIGS. 39A-39D are perspective (FIG. 39A), cross-sectional (FIG. 39B) and top (FIGS. 39C and 39D) views of a distal portion of a tissue modification device according to one embodiment of the present invention.
FIGS. 40A-40F are perspective (FIG. 40A), cross-sectional perspective (FIG. 40B), and cross-sectional side (FIGS. 40C-40F) views of a distal portion of a tissue modification device according to an alternative embodiment of the present invention.



DETAILED DESCRIPTION OF THE INVENTION
Methods, apparatus and systems for modifying tissue in a patient are provided. Although the following description and accompanying drawing figures generally focus on tissue modification in spine, in various alternative embodiments any of a number of tissues in any of a number of anatomical locations in a patient may be modified.
Referring to FIG. 2, in one embodiment a tissue modification device 102 may include an elongate body 108 having a proximal portion 107 and a distal portion 109, a handle 104 with an actuator 106 coupled with proximal portion 107, one or more tissue modifying members 110, and one or more protective surfaces 112. In various embodiments, some of which are described further below, modification device 102 may be introduced into an area for performing a treatment, such as a spine, using any of a number of different introduction methods, devices and systems 100. In FIG. 2, for example, modification device 102 extends through an introducer device 114 placed through a first incision 240 on the patient's back and into the central spinal canal. Modification device 102 is advanced along a guide member 116, which extends through introducer member 114, through the intervertebral foramen between two adjacent vertebrae (only part of one vertebra is shown in FIG. 2), and out a second (or “distal”) incision 242 on the back. In some embodiments, as shown, guide member has a beveled distal tip 117 for facilitating advancement of guide member 116 through tissue.
FIGS. 41-46 are partial cross-sectional views through a patient's spine, illustrating a double barrel system used with additional methods and apparatus for placement of an abrasion apparatus through the neural foramina for selective surgical removal of tissue.
Generally, tissue modification device 102 may be advanced to a position in the spine such that tissue modifying member 110 faces target tissue to be modified, such as buckled, thickened or otherwise impinging ligamentum flavum tissue as shown in FIG. 2. Modification device 102 is configured such that when tissue modifying member 110 faces the target tissue, protective surface(s) 112 face non-target tissue. Protective surface 112 may be simply a length of elongate body 108 or may have one or more protective features, such as a widened diameter, protective or lubricious coating, extendable barrier, drug-eluting coating or ports, or the like. In some instances, protective surface(s) 112 may act as “non-tissue-modifying” surfaces, in that they may not substantially modify the non-target tissue. In alternative embodiments, protective surface(s) 112 may affect non-target tissue by protecting it in some active way, such as by administering one or more protective drugs, applying one or more forms of energy, providing a physical barrier, or the like.
In some embodiments, once tissue modification device 102 is positioned such that tissue modifying member 110 faces target tissue and protective surface 112 faces non-target tissue, an anchoring force may be applied at or near distal portion 109 of elongate body 108, either inside or outside the patient's body. A tensioning force may also be applied at or near proximal portion 107 of elongate body 108, such as by pulling on handle 104 (one-directional arrows), and actuator 106 may be used (two-headed arrow) to activate tissue modifying member(s) 110 to modify target tissue. In the example shown, anchoring force is applied near distal portion 109 by a user's hand 244, and handle 104 is pulled proximally (arrows) to apply tensioning force. In an alternative embodiment, hand 244 may grasp guide member 116 at or near its distal portion 117 and thus apply anchoring force to it, thus also applying anchoring force to elongate body 108. In one variation of such an embodiment, elongate body 108 or handle 104 may optionally be adjustably clamped to guide member 116 to further enhance or facilitate application of anchoring force to elongate body 108. Tissue modification via tissue modifying members 110 may include cutting, ablating, dissecting, repairing, reducing blood flow in, shrinking, shaving, burring, biting, remodeling, biopsying, debriding, lysing, debulking, sanding, filing, planing, heating, cooling, vaporizing, delivering a drug to, and/or retracting the target tissue. Once tissue has been modified, tissue modification device 102 and any introducer devices 114, guide members 116 or other devices may be removed from the patient.
In various embodiments of the apparatus, tissue modifying member(s) 110 may be disposed along any suitable length of body 108. In one embodiment, for example, such as an embodiment of the device to be used in a spinal treatment, tissue modifying members 110 may be disposed along a length of the device measuring no longer than 10 cm, and preferably no more than 6 cm, and even more preferably no more than 3 cm. In various embodiments, tissue modifying member(s) 110 may include a rongeur, a curette, a scalpel, one or more cutting blades, a scissors, a forceps, a probe, a rasp, a file, an abrasive element, one or more small planes, an electrosurgical device, a bipolar electrode, a unipolar electrode, a thermal electrode, a rotary powered mechanical shaver, a reciprocating powered mechanical shaver, a powered mechanical burr, a laser, an ultrasound crystal, a cryogenic probe, a pressurized water jet, a drug dispensing element, a needle, a needle electrode, or some combination thereof. In various embodiments, all tissue modifying members 110 may be mobile relative to the elongate body, all may be static, or some may be mobile and some may be static. These and other aspects and embodiments are described further below.
Turning now to FIG. 3A-3I, more detailed figures of one embodiment of tissue modification device 102 are shown. Referring to FIG. 3A, tissue modification device 102 may include elongate body 108 having proximal portion 107 and distal portion 109, a window 111 disposed along elongate body 108, two tissue modifying blades 110 exposed through window 111, and handle 104 with actuator 106 coupled with proximal portion 107. In the embodiment shown, the tissue modifying members comprise blades 110, although in alternative embodiments other tissue modifying members may be added or substituted.
In various embodiments, elongate body 108 may have any number of dimensions, shapes, profiles and amounts of flexibility. For example, distal portion 109 is shown having a curved shape to demonstrate that at least a portion of elongate body 108 may be flexible. In various embodiments, elongate body 108 may have one or more of a round, ovoid, ellipsoid, flat, cambered flat, rectangular, square, triangular, symmetric or asymmetric cross-sectional shape. As shown in FIGS. 3C and 3D, in the pictured embodiment, elongate body 108 has a relatively flat configuration, which may facilitate placement of body 108 between target and non-target tissues. Distal portion 109 of body 108 may be tapered, to facilitate its passage into or through narrow spaces as well as through small incisions on a patient's skin. Body 108 may also include a slightly widened portion around the area of window 111 and blades. In one embodiment, such as an embodiment used for modifying tissue in a spine, body 108 may have a small profile, such as having a height of not more than 10 mm at any point along its length and a width of not more than 20 mm at any point along its length, or more preferably a height not more than 5 mm at any point along its length and a width of not more than 10 mm at any point along its length, or even more preferably a height not more than 2 mm at any point along its length and a width of not more than 4 mm at any point along its length. Body 108 may be long enough to extend through a first incision on a patient, between target and non-target tissue, and out a second incision on a patient. Alternatively, body 108 may be long enough to extend through a first incision, between the target and non-target tissue, and to an anchoring location within the patient. In another alternative embodiment, body 108 may be long enough to extend through a first incision, between the target and non-target tissue, to a location nearby but distal to the target tissue within the patient, with some portion of tissue modification device 102 anchored to guide member 116. In some embodiments, elongate body 108 includes at least one feature for allowing passage of the body over a guidewire or other guide member or to allow passage of one or more guide members over or through body 108. For example, in various embodiments body 108 may include one or more guidewire lumens, rails, tracks, lengthwise impressions or some combination thereof.
In one embodiment, elongate body 108 is predominantly flexible along its length and comprises any suitable flexible material, such as thin, flexible metals, plastics, fabrics or the like. In some embodiments, it may be advantageous to include one or more rigid sections in elongate body 108, such as to impart pushability to a portion of body 108 or to facilitate application of force to tissue modification members 110 without causing unwanted bending or kinking of elongate body 108. In such embodiments, rigidity may be conferred by using additional materials in body 108 or by making the rigid portions thicker or wider or of a different shape.
Handle 104 may have any suitable configuration according to various embodiments. Similarly, actuator 106 may include any of a number of actuation devices in various embodiments. In the embodiment shown in FIG. 3A, actuator 106 comprises a trigger or moving handle portion, which is grasped by a user and pulled or squeezed toward handle 104 to bring blades 110 together to cut tissue. In an alternative embodiment, actuator 106 instead may include a switch or button for activating a radiofrequency surgical ablation tissue modifying member. In yet another embodiment, actuator 106 may include a combination trigger and switch, one or more pull wires, any suitable form of lever and/or some combination thereof.
FIGS. 3B-3D show in greater detail a portion of tissue modification device 102. In these figures, window 111 and blades 110 are more clearly seen. In one embodiment, at least a portion of elongate body 108 and blades 110 may have a slightly curved configuration. In alternative embodiments, at least a portion of elongate body 108 and blades 110 may be flat. In other alternative embodiments, tissue modification members such as blades 110 may be proud to elongate body 108.
Blades 110 include a distal 110a and a proximal blade 110b that reside at the distal and proximal edges, respectively, of window 111 of elongate body 108. Window 111 of body 108 may accommodate both soft and hard tissue when the device is forcibly applied to the surface of a target tissue site. The top view of the distal portion of elongate body 108, shown in FIG. 3C, depicts the angled edges of distal blade 110a and proximal blade 110b, which facilitate shearing of target tissue. In alternative embodiments, blades 110 may have any of a number of alternative shapes and configurations. The distal portion of body 108 may have a very low profile (height compared to width), as shown in side view FIG. 3D, where only blades 110 protrude from the top surface of the elongate body 108. In one embodiment, also as shown in FIG. 3D, a guidewire tube 120 (or lumen) may extend from (or be coupled with) a lower surface of elongate body 108. The lower surface of elongate body 108 is an example of a protective or non-tissue-modifying surface.
In one embodiment, distal blade 110a is coupled with two pull-wires 118, as seen in FIGS. 3C, 3E and 3F. Pull-wires 118 coupled to and translated by actuator 106 on handle 104 may be used to drive distal blade 110a proximally to contact the cutting edge of proximal blade 110b, thus cutting tissue. Other alternative mechanisms for driving blades 110, such as gears, ribbons or belts, magnets, electrically powered, shape memory alloy, electro magnetic solenoids and/or the like, coupled to suitable actuators, may be used in alternative embodiments. As mentioned, in one embodiment distal blade 110a and/or proximal blade 110b may have an outwardly curvilinear shape along its cutting edge. Alternatively, distal blade 110a may have a different blade shape, including flat, rectilinear, v-shaped, and inwardly curvilinear (concave vs. convex). The cutting edge of either blade 110 may have a sharp edge formed by a simple bevel or chamfer. Alternatively or in addition, a cutting edge may have tooth-like elements that interlock with a cutting edge of an opposing blade, or may have corrugated ridges, serrations, rasp-like features, or the like. In various embodiments, both blades 110 may be of equal sharpness, or alternatively one blade 110 may be sharp and the other substantially flat to provide a surface against which the sharp blade 110 may cut. Alternately or in addition, both cutting edges may be equally hard, or a first cutting edge may be harder than a second, the latter of which deflects under force from the first harder edge to facilitate shearing of the target tissue.
FIGS. 3E and 3F show cross-sectional views through elongate body at lines A-A and B-B, respectively, of FIG. 3C. In some embodiments, all or a portion of elongate body 108, such as the lower surface shown in FIG. 3E, may include a lubricious surface for facilitating manipulation of the tool in the surgical space and at the anatomical site. The lubricious lower surface also provides a barrier between blades 110 and non-target tissue in the surgical space. The lower surface may include a guide member lumen 120 to accommodate a guidewire or other access device or rail. FIG. 3E shows distal blade 110 coupled with pull wires 118. FIG. 3F shows proximal blade 110b, which is not coupled with pull wires 118 but rather fixed to body 108. In various alternative embodiments, proximal blade 110b may be movable distally while distal blade 110a is static, both blades may be moved toward one another, or a different number of blades may be used, such as one blade drawn toward a backstop or more than two blades, one or more of which may be mobile. In various alternative embodiments, guide member lumen 120 may be accommodated on a side surface or more centrally within elongate body 108. In further alternative embodiments, the one or more guide member lumens 120 may comprise one or more various cross sectional shapes, for example substantially round, substantially oval, or substantially rectabular, to accommodate alternative guide members, for example flat or rectangular guidewires, needles or rails. In still other alternative embodiments guide member lumen 120 may be adjustably coupled with the elongate body 108 to enable manipulation of the location of the elongate body 108 and therefore the tissue modifying members 110 relative to the guiding member.
Referring now to FIGS. 3G-3I, blades 110 are shown in their closed position. In one embodiment, when distal blade 110a is drawn proximally to cut tissue, at least some of the cut tissue is captured in a hollow interior portion of elongate body 108. Various embodiments may further include a cover, a cut tissue housing portion and/or the like for collecting cut tissue and/or other tissue debris. Such collected tissue and debris may then be removed from the patient during or after a tissue modification procedure. During a given tissue modification procedure, distal blade 110a may be drawn proximally to cut tissue, allowed to retract distally, and drawn proximally again to further cut tissue as many times as desired to achieve a desired amount of tissue cutting.
Blades 110 may be made from any suitable metal, polymer, ceramic, or combination thereof. Suitable metals, for example, may include but are not limited to stainless steel, nickel-titanium alloy, tungsten carbide alloy, or cobalt-chromium alloy, for example, ElgiloyTM (Elgin Specialty Metals, Elgin, Ill., USA), ConichromeTM (Carpenter Technology, Reading, Pa., USA), or PhynoxTM (Imphy SA, Paris, France). In some embodiments, materials for the blades or for portions or coatings of the blades may be chosen for their electrically conductive or thermally resistive properties. Suitable polymers include but are not limited to nylon, polyester, DacronTM, polyethylene, acetal, DelrinTM (DuPont, Wilmington, Del.), polycarbonate, nylon, polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). In some embodiments, polymers may be glass-filled to add strength and stiffness. Ceramics may include but are not limited to aluminas, zirconias, and carbides. In various embodiments, blades 110 may be manufactured using metal injection molding (MIM), CNC machining, injection molding, grinding and/or the like. Pull wires 118 be made from metal or polymer and may have circular, oval, rectangular, square or braided cross-sections. In some embodiments, a diameter of a pull wire 118 may range from about 0.001′′-0.050′′, and more preferably from about 0.010′′-0.020′′.
Depending on the tissue to be treated or modified, activating blades 110 (or other tissue modifying members in alternative embodiments) may cause them to modify target tissue along an area having any of a number of suitable lengths. In use, it may also be advantageous to limit the extent of action of blades 110 or other tissue modifying members to a desired length of tissue, thus not allowing blades 110 to affect tissue beyond that length. In so limiting the effect of blades, unwanted modification of, or damage to, surrounding tissues and structures may be limited or even eliminated. In one embodiment, for example, where the tissue modification device is used to modify tissue in a spine, blades 110 may operate along a length of target tissue of no more than 10 cm, and preferably no more than 6 cm, and even more preferably no more than 3 cm. Of course, in other parts of the body and to address other tissues, different tissue modification devices may be used and tissue modifying members may have many different lengths of activity. In one embodiment, to facilitate proper location of tissue modifying members, such as blades 110, relative to target tissue, the tissue modifying members and/or the elongate body and/or one or more additional features intended for just such a purpose may be composed of a material readily identifiable via x-ray, fluoroscopic, magnetic resonance or ultrasound imaging techniques.
In various embodiments, a number of different techniques may be used to prevent blades 110 (or other tissue modifying members) from extending significantly beyond the target tissue. In one embodiment, for example, preventing blades 110 from extending significantly beyond the target tissue involves holding tissue modification device 102 as a whole predominantly stable to prevent device 102 from translating in a direction toward its proximal portion or toward its distal portion while activating blades 110. Holding device 102 stable is achieved by anchoring one end of the device and applying tensioning force at or near the other end, as described further below.
In the embodiment shown in FIGS. 3A-3I, pull wires 118 are retracted proximally by squeezing actuator 106 proximally. In an alternative embodiment, squeezing actuator 106 may cause both blades 110 to translate inward so that they meet approximately in the middle of window 111. In a further embodiment, distal blade 110a may be returned to it's starting position by a pulling force generated from the distal end of device 102, for example by using a distal actuator that is attached to distal wires, or by pulling on the distal guide member which is attached to distal blade 110a. In yet another alternative embodiment, proximal blade 110b may be moved to cut by a pulling force generated from the distal end of device 102, for example by using a distal actuator that is attached to distal wires, or by pulling on the distal guide member which is attached to proximal blade 110b. In yet another embodiment, squeezing actuator 106 may cause proximal blade 110b to move distally while distal blade 110a stays fixed. In other alternative embodiments, one or more blades 110 may move side-to-side, one or more blades 110 may pop, slide or bow up out of window 111 when activated, or one or more blades 110 may expand through window. In another embodiment, one or more blades 110 and/or other tissue modifying members of device 102 may be powered devices configured to cut, shave, grind, abrade and/or resect target tissue. In other embodiments, one or more blades may be coupled with an energy transmission device, such as a radiofrequency (RF) or thermal resistive device, to provide energy to blade(s) 110 for cutting, ablating, shrinking, dissecting, coagulating or heating and thus enhancing tissue modification. In another embodiment, a rasp or file may be used in conjunction with or coupled with one or more blades. In any of these embodiments, use of actuator 106 and one or more moving blades 110 provides for tissue modification with relatively little overall translation or other movement of tissue modification device 102. Thus, target tissue may be modified without extending blades 110 or other tissue modification members significantly beyond an area of target tissue to be treated.
Referring now to FIGS. 4A-4C, in an alternative embodiment, a tissue modification device 202 may include an elongate body 208 having a proximal portion and a distal portion 209, a handle 204 and actuator 206 coupled with proximal portion, and a window 211 and tissue modifying member 210 disposed near distal portion 209. As seen more clearly in FIGS. 4B and 4C, in the embodiment shown, tissue modifying member 210 comprises an RF electrode wire loop. Wire loop 210 may comprise any suitable RF electrode, such as those commonly used and known in the electrosurgical arts, and may be powered by an internal or external RF generator, such as the RF generators provided by Gyrus Medical, Inc. (Maple Grove, Minn.). Any of a number of different ranges of radio frequency may be used, according to various embodiments. For example, some embodiments may use RF energy in a range of between about 70 hertz and about 5 megahertz. In some embodiments, the power range for RF energy may be between about 0.5 Watts and about 200 Watts. Additionally, in various embodiments, RF current may be delivered directly into conductive tissue or may be delivered to a conductive medium, such as saline or Lactate Ringers solution, which may in some embodiments be heated or vaporized or converted to plasma that in turn modifies target tissue. Distal portion 209 includes a tapered tip, similar to that described above, to facilitate passage of elongate body 208 into narrow anatomical sites. Handle 204 and actuator 206 are similar to those described above, although in the embodiment of FIGS. 4A-4C, actuator 206 may be used to change the diameter of the wire loop 210. Using actuator 206, wire loop 210 may be caused to extend out of window 211, expand, retract, translate and/or the like. Some embodiments may optionally include a second actuator (not shown), such as a foot switch for activating an RF generator to delivery RF current to an electrode.
Elongate body 208 may be fabricated from any suitable material and have any of a number of configurations. In one embodiment, body 208 comprises a metal tube with a full-thickness slit (to unfold the tube into a flat form—not shown) or stiffening element (not shown). The split tube provides for a simple manufacturing process as well as a conductive pathway for bi-polar RF operation. The tube may include a waist region 220.
Referring to FIG. 4C, insulators 222 may be disposed around a portion of wire loop 210 so that only a desired portion of wire loop 210 may transfer RF current into the tissue for tissue modifying capability. Wire loop 210, covered with insulators 222 may extend proximally into support tubes 218. In various alternative embodiments, an electrode tissue modifying member (of which wire loop 210 is but one example) may be bipolar or monopolar. For example, as shown in FIG. 4C, a sleeve 224 housed toward the distal portion of window 211 may act as a return electrode for wire loop 210 in a bipolar device. Wire loop electrodes 210 may be made from various conductive metals such as stainless steel alloys, nickel titanium alloys, titanium alloys, tungsten alloys and the like. Insulators 222 may be made from a thermally and electrically stable polymer, such as polyimide, polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), polyamide-imide, or the like, and may optionally be fiber reinforced or contain a braid for additional stiffness and strength. In alternative embodiments, insulators 222 may be composed of a ceramic-based material.
In one embodiment, wire loop 210 may be housed within elongate body 208 during delivery of tissue modification device 202 into a patient, and then caused to extend up out of window 211, relative to the rest of body 208, to remove tissue. Wire loop 210 may also be flexible so that it may pop or bow up out of window 211 and may deflect when it encounters hard tissue surfaces. Wire loop 210 may have any of a number of shapes, such as curved, flat, spiral or ridged. Wire loop 210 may have a diameter similar to the width of body 208, while in alternative embodiments it may expand when extended out of window 211 to have a smaller or larger diameter than that of body 208. Pull wires (not shown) may be retracted proximally, in a manner similar to that described above, in order to collapse wire loop 210, decrease the diameter and lower the profile of the wire loop 210, and/or pull wire loop 210 proximally to remove tissue or be housed within body 208. The low profile of the collapsed wire loop 210, facilitates insertion and removal of tissue modification device 202 prior to and after tissue modification. As the wire loop 210 diameter is reduced, support tubes 218 deflect toward the center of elongate body 208.
In an alternative embodiment (not shown), tissue modification device 202 may include multiple RF wire loops 210 or other RF members. In another embodiment, device 202 may include one or more blades as well as RF wire loop 210. In such an embodiment, wire loop 210 may be used to remove or otherwise modify soft tissues, such as ligamentum flavum, or to provide hemostasis, and blades may be used to modify hard tissues, such as bone. In other embodiments, as described further below, two separate tissue modification devices (or more than two devices) may be used in one procedure to modify different types of tissue, enhance modification of one type of tissue or the like.
In other alternative embodiments, tissue modification devices 202 may include tissue modifying members such as a rongeur, a curette, a scalpel, a scissors, a forceps, a probe, a rasp, a file, an abrasive element, one or more small planes, a rotary powered mechanical shaver, a reciprocating powered mechanical shaver, a powered mechanical burr, a laser, an ultrasound crystal a cryogenic probe, a pressurized water jet, a drug dispensing element, a needle, a needle electrode, or some combination thereof. In some embodiments, for example, it may be advantageous to have one or more tissue modifying members that stabilize target tissue, such as by grasping the tissue or using tissue restraints such as barbs, hooks, compressive members or the like. In one embodiment, soft tissue may be stabilized by applying a contained, low-temperature substance (for example, in the cryo-range of temperatures) that hardens the tissue, thus facilitating resection of the tissue by a blade, rasp or other device. In another embodiment, one or more stiffening substances or members may be applied to tissue, such as bioabsorbable rods.
Referring now to FIGS. 5A-5D, one embodiment of a method for modifying tissue in a spine is demonstrated in simplified, diagrammatic, cross-sectional views of a portion of a patient's back and spine. FIG. 5A shows a portion of the patient's back in cross section, with a portion of a vertebra, the spinal cord with branching nerve roots, and target tissue, which in this illustration is the ligamentum flavum and possibly a portion of the facet capsule. The target tissue is typically impinging directly on one or more of the group including nerve roots, neurovascular structures, dorsal root ganglia, cauda equina, or individual nerves.
In FIG. 5B, tissue modification device 102 has been positioned in the patient's back to perform a tissue modification procedure. Various methods, devices and systems for introducing device 102 into the patient and advancing it to the position for modifying tissue are described in further detail below. Generally, device 102 may be positioned via a percutaneous or open surgical procedure, according to various embodiments. In one embodiment, device 102 may be inserted into the patient through a first incision 240, advanced into the spine and between target tissue and non-target tissue (such as spinal cord, nerve roots, nerves and/or neurovascular tissue), and further advanced so a distal portion of elongate body 108 exits a second (or distal) incision 242 to reside outside the patient. In positioning device 102, one or more tissue modifying members (not shown) are positioned to face the target tissue, while one or more protective portions of elongate body 108 face non-target tissue.
Referring to FIG. 5C, once device 102 is positioned in a desired location, anchoring force may be applied at or near the distal portion of elongate body 108. In one embodiment, applying anchoring force involves a user 244 grasping body 108 at or near its distal portion. In alternative embodiments, as described further below, anchoring force may be applied by deploying one or more anchor members disposed at or near the distal portion of body 108, or by grasping a guidewire or other guide member extending through at least part of body 108. Once the anchoring force is applied, proximally-directed tensioning force may be applied to device 102, such as by pulling proximally on handle 104 (one-directional, diagonal arrows). This tensioning force, when applied to the substantially anchored device 102, may help urge the tissue modifying member(s) against the target tissue (one-directional, vertical arrows near target tissue), thus enhancing contact with the target tissue and facilitating its modification. With the tissue modifying member(s) contacting the target tissue, actuator 106 may be squeezed or pulled (two-headed arrow) to cause the tissue modifying member(s) to modify tissue. (Alternative actuators may be activated in different ways in alternative embodiments.)
In various alternative embodiments, certain of the above-described steps may be carried out in different order. For example, in one embodiment the distal portion of elongate body 108 may be anchored within or outside the patient before the tissue modifying members are positioned adjacent the target tissue. In another alternative embodiment, the proximal portion of device 102 may be anchored, and the tensioning force may be applied to the distal portion of device 102. In yet another embodiment, tensioning force may be applied to both ends of the device. In yet another embodiment, a second handle and actuator may be coupled with the distal end of body 108 after it exits the patient's back, allowing tensioning forces as well as tissue modifying actuation to occur at both the proximal and distal portions of device 102. By anchoring one end of device 102 and applying tensioning force to the opposite end, contact of the tissue modifying members with the target tissue is enhanced, thus reducing or eliminating the need for translating or otherwise moving device 102 as a whole and reducing the overall profile and the resulting access pathway required to position the device. Reducing movement and profile of device 102 and using tissue modifying members confined to a relatively small area of device 102 helps facilitate target tissue modification while minimizing or eliminating damage to surrounding tissues or structures.
As mentioned above, tissue may be modified using one tissue modification device or multiple devices, according to various embodiments. In one embodiment, for example, an RF electrosurgical tissue modification device may be used in the patient to remove soft tissue such as ligament, and a bladed tissue modification device such as a rongeur may then be used to remove additional soft tissue, calcified soft tissue, or hard tissue such as bone. In some embodiments, such multiple devices may be inserted, used and removed serially, while in alternative embodiments such devices may be inserted into the patient at the same time to be used in combination.
Referring to FIG. 5D, using one or more tissue modification devices 102, a desired amount of target tissue may be removed from more than one area in the spine. FIGS. 5A-5C demonstrate removal of target tissue on one side of the spine, and that method or a similar method may also be used to remove target tissue on an opposite side of the spine, as shown in FIG. 5D, where target tissue has been removed from both sides. That the desired amount of tissue has been removed may be confirmed by tactile feedback from the device or from a separate device, by testing nerve conduction through one or more previously impinged nerves, by testing blood flow through one or more previously impinged blood vessels, by passing (independently or over the guide member) a measurement probe or sound through the treated portion, through one or more radiographic tests, through some combination thereof, or by any other reasonable means.
Referring now to FIG. 6A, tissue modification device 102 is shown with one embodiment of a distal anchoring member 250 deployed at the patient's skin. In various embodiments, anchoring members may include but are not limited to one or more handles, barbs, hooks, screws, toggle bolts, needles, inflatable balloons, meshes, stents, wires, lassos, backstops or the like. In some embodiments, anchoring members 250 may be disposed at the extreme distal portion 109 of elongate body 108, while in other embodiments anchoring members 250 may be located more proximally. In the embodiment shown, anchoring members 250 are deployed at the patient's skin. In an alternative embodiment, anchoring may be achieved outside the patient by deploying one or more anchoring members 250 above the skin and having a user grasp the anchoring members 250. In an alternative embodiment, anchoring may be achieved outside the patient by deploying one or more anchoring members 250 above the skin and having a user grasp anchoring members 250, after tissue modification device 102 has been anchored to the guide member. In another alternative embodiment, anchoring may be achieved outside the patient by attaching anchoring member 250 to an external device, for example one that is mounted on the patient or on the procedure table. In a further alternative embodiment, anchoring may be achieved outside the patient by attaching the guide member to an external device, for example one that is mounted to on the patient or on the procedure table, after tissue modification device 102 has been anchored to the guide member. Anchoring members 250 generally are deployable from a first, contracted configuration to facilitate delivery of device 102, to a second, expanded configuration to facilitate anchoring. This change in configuration may be achieved, for example, by using shape memory or super-elastic materials, by spring loading anchoring members 250 into body 108 or the like. In most embodiments, anchoring members 250 may also be collapsed down into the first, contracted configuration after a tissue modification procedure has been performed, to facilitate withdrawal of device 102 from the patient. In an alternative embodiment, anchoring members 250 may detach from body 108 and may be easily removable from the patient's skin.
FIG. 6B shows tissue modification device 102 with an alternative embodiment of a distal anchoring member 260. Here, distal anchoring member 260 includes multiple hooks or barbs extended out the distal portion 109 of elongate body 108 within the patient's back. In using such an embodiment, it may not be necessary to pass guide member 117 through a second, distal incision on the patient, although in some embodiments guide member 117 may extend significantly beyond distal portion 109. Anchoring member(s) 260, according to various embodiments, may be deployed so as to anchor to bone, ligament, tendon, capsule, cartilage, muscle, or any other suitable tissue of the patient. They may be deployed into vertebral bone or other suitable tissue immediately adjacent an intervertebral foramen or at a location more distant from the intervertebral foramen. When a tissue modification procedure is complete, anchoring members 260 are retracted within elongate body for removal of device 102 from the patient.
Referring now to FIGS. 7A-7S, a system and method for introducing a tissue modification device into a spine is demonstrated. This system and method may be referred to as an “access system” or “access method,” in that they provide or facilitate gaining access to a target tissue to be modified. Of course, the embodiment shown is merely one exemplary embodiment, and any of a number of other suitable methods, devices or systems may be used to introduce one or more devices for modifying tissue in spine. For example, in one alternative embodiment a spinal tissue modification procedure may be carried out through an open surgical approach. Therefore, the following description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is defined in the claims.
Referring to FIG. 7A, in one embodiment a device delivery method first involves advancing an introducer cannula 300 coupled with a stylet 302 into the patient's back. Cannula 300 and stylet 302 are then passed between adjacent vertebrae and into the ligamentum flavum or an adjacent spinal ligament, as shown further in FIG. 7B. As shown in FIG. 7C, when the distal tip of cannula is positioned as desired, stylet 302 is removed. Referring to FIGS. 7D and 7E, a loss of resistance syringe 304 including a plunger 310, barrel 308 and fluid and/or air 306, is coupled with the proximal portion of cannula 300. The distal portion of cannula 300 is advanced through the ligamentum flavum until it enters the central spinal canal where a loss of resistance to pressure placed on plunger 310 is encountered, and fluid and/or air 306 is injected into central spinal canal to confirm correct placement of cannula 300 as shown in FIG. 7E. Syringe 304 is then removed, as in FIG. 7F, and a guidewire 312 with a non-rigid, atraumatic tip is advanced through cannula 300 into the central spinal canal, as in FIG. 7G. Next, cannula 300 is removed, as in FIG. 7H, leaving behind guidewire 312. As shown in FIGS. 7I and 7J, an introducer sheath 114, coupled with a dilator 314, is then advanced over guidewire 312 to position a distal portion of sheath 114 at a desired location within the spine. Dilator 314 and guidewire 312 are then removed, as in FIG. 7K.
Once introducer sheath 114 is in place, one or more curved or steerable guide devices 318 may be advanced through it to desired positions in and/or through the spine, as shown in FIGS. 7L and 7M. One or more guide members 116, may then be advanced through the guide device 318, as shown in FIGS. 7N-7P. Finally, guide device 318 may be removed, as in FIG. 7Q, and elongate body 108 of tissue modification device 102 may be advanced over guide member 116 and through introducer sheath 114 to a desired position in the spine, as in FIG. 7R. As shown in FIG. 7S, elongate body 108 may be tensioned to urge tissue modifying members 110 against target tissue, as shown with arrows at opposite ends of device 102, while distal portion 109 is anchored, in this case by hand 244. In an alternative embodiment, guide member 116 may be tensioned to urge tissue modifying members 110 against target tissue as shown in FIG. 7R.
Once tissue modification device 102 is in a desired position, tissues which may be modified in various embodiments include, but are not limited to, ligament, tendon, tumor, cyst, cartilage, scar, “bone spurs,” inflammatory and bone tissue. In some embodiments, modifying the target tissue reduces impingement of the tissue on a spinal cord, a branching nerve or nerve root, a dorsal root ganglia, and/or vascular tissue in the spine. Actuator 106 on handle 104 is activated to modify target tissue using tissue modification member(s) 110, while elongate body 108 is held relatively stable by hand 244 and by tension force applied to handle 104.
In various embodiments, the system and method described immediately above may include additional features or steps, may have fewer features or steps, may have an alternate order of implementation of steps, or may have different features or steps. For example, in some embodiments placement of device 102 will be performed in a medial-to-lateral direction (relative to the patient), while in alternative embodiments device placement will be performed lateral-to-medial. In some embodiments, one or more components of the system described may be anchored to the patient, such as guide member 116 or introducer sheath 114. In various embodiments, one or more guide members 116 may include one or more wires, rails or tracks and may be inserted through guide device 318, introducer sheath 114 without guide device 318, cannula 300, an epidural needle, a lumen of an endoscope, a lumen of a tissue shield or barrier device, a curved guide device 318 placed through a lumen of an endoscope, or the like. In other embodiments, for example, guide device 318 may be placed through introducer cannula 300 and then introducer sheath 114 may be passed over guide device 318. Tissue modification device 102 may similarly be inserted with or without using any of these devices or components in various combinations. Various guidewires 312, guide devices 318 and/or guide members 116 may be pre-shaped to have one or more curves, may be steerable, and/or may include one or more rails, tracks, grooves, lumens, slots, partial lumens, or some combination thereof.
In some embodiments, tissue modification device 102 is inserted through one or more hollow devices as described above (such as introducer sheath 114, as shown, or cannula 300 in an alternative embodiment) in such a way that device 102 expands upon extending out of a distal portion of the hollow delivery device thereby assuming a wider profile for modifying a greater amount of target tissue from a single location. In an alternative embodiment, device 102 retains the same overall profile during insertion and during use. In some embodiments, one or more delivery devices will remain in the patient during use of tissue modification device 102, while in alternative embodiments all delivery devices are removed from the patient when tissue modification device 102 is operating. In some embodiments, tissue modification device 102 may be slidably coupled with one or more delivery devices during delivery and/or during use. In one embodiment, tissue modification device 102 is advanced through introducer sheath 114 and sheath 114 is used as an irrigation and evacuation lumen to irrigate the area of the target tissue and evacuate removed tissue and other debris, typically by applying a vacuum. In alternative embodiments, tissue modification device 102 may include an irrigation and/or evacuation lumen to irrigate an area of the target tissue and evacuate removed tissue and other debris.
Some embodiments of an access system for facilitating tissue modification may further include one or more visualization devices (not shown). Such devices may be used to facilitate placement of the access system for introducing the tissue modification device, to facilitate tissue modification itself, or any combination of these functions. Examples of visualization devices that may be used include flexible, partially flexible, or rigid fiber optic scopes, rigid rod and lens endoscopes, CCD or CMOS chips at the distal portion of rigid or flexible probes, LED illumination, fibers or transmission of an external light source for illumination or the like. Such devices may be slidably couplable with one or more components of an access system or may be slidably or fixedly coupled with a tissue modification device. In other embodiments, additional or alternative devices for helping position, use or assess the effect of a tissue modification device may be included. Examples of other such devices may include one or more neural stimulation electrodes with EMG or SSEP monitoring, ultrasound imaging transducers external or internal to the patient, a computed tomography (CT) scanner, a magnetic resonance imaging (MRI) scanner, a reflectance spectrophotometry device, and a tissue impedance monitor disposed across a bipolar electrode tissue modification member or disposed elsewhere on a tissue modification device or disposed on the access system.
Referring now to FIGS. 8A-8E, in an alternative embodiment, a tissue modification device and optionally one or more introduction/access devices may be positioned in a patient using an open surgical technique. As shown in FIG. 8A, for example, in one embodiment an open surgical incision is made on a patient's back, and two retractors 402 are used to expose a portion of the patient's vertebra. As shown in FIG. 8B, an introducer sheath 414 may then be inserted through the incision, between retractors 402. As in FIG. 8C, a curved guide device 418 may then be inserted through introducer sheath 414. Guide device 418 extends into the epidural space and through the intervertebral foramen as shown in FIG. 8D.
In some embodiments, a curved and cannulated thin, blunt probe may be placed directly through the open incision into the epidural space of the spine, or alternatively may be placed through introducer sheath 414. The probe tip may be advanced to or through a neural foramen. Such a probe may be similar in shape, for example, to a Woodson elevator, Penfield 3, hockey stick probe, ball tipped probe, or the like. In alternative embodiments, probes that may be manually bent to change their shapes, or probes with articulating tips, or probes with shape lock portions, and/or probes having grooves instead of cannulas may be used.
As shown in FIGS. 8D-8E, a substantially straight, flexible guidewire 420 with a sharp tip 422 may then be inserted through curved guide device 418 and advanced so that its distal portion with sharp tip 422 extends outside the patient's back at a location separate from the open incision (FIG. 8E). Guide device 418 may then be removed, as in FIG. 8F, and in subsequent steps a tissue modification device may be inserted over guide wire 420 and through introducer sheath 414 and used to modify tissue as described in more detail above. In an alternative embodiment, a curved, flexible cannula may be inserted through the curved guide device, until it extends lateral to the neural foramen, after which a substantially straight, flexible guidewire with a sharp tip may then be inserted through curved cannula and advanced so that its distal portion with sharp tip extends outside the patient's back.
Referring now to FIGS. 9A and 9B, another alternative open surgical access method is shown. In FIG. 9A, a curved guide device 446 is shown in place through the epidural space and intervertebral foramen, and a guidewire 440 with a beveled distal tip 442 is about to be advanced through guide device 446. As shown in FIG. 9B, in this embodiment, guidewire 440 is directed by guide device 446 back through the open incision through which the various access devices are introduced. In such an embodiment, then, only one incision is created and the proximal and distal portions of one or more devices extend out of the patient's back through the same incision.
In various alternative embodiments, open surgical access may be through exposure down to a vertebral lamina, through ligamentum flavum without lamina removal, through ligamentum flavum with partial or complete lamina removal, through ligamentum flavum with or without lamina removal with partial or complete medial facet joint removal, through open exposure and out through skin laterally, through open exposure and back out through the open exposure, or through a lateral open exposure that accesses the neural foramen from the lateral side. One or more visualization devices may be used with open surgical access procedures as well as with percutaneous or other less invasive procedures. In another alternative embodiment (not shown), a tissue modification device may be placed in the patient directly, without any introduction devices.
Referring now to FIGS. 10A-10E, in the embodiments described above, the tissue modification devices 102, 202 include at least one non-tissue-modifying (or “protective”) portion, side or surface. The non-tissue-modifying portion is located on tissue modification device 102, 202 so as to be positioned adjacent non-target tissue when tissue modifying members 110, 210 are facing the target tissue. The non-tissue-modification surface of the device is configured so as to not modify or damage tissue, and thus the non-target tissue is protected from unwanted modification or damage during a tissue modification procedure. Alternatively, in some embodiments, a protective surface or portion of tissue modification device 102, 202 may actually modify non-target tissue in a protective manner, such as by delivering a protective drug, coating, fluid, energy or the like to the non-target tissue.
Optionally, in some embodiments, tissue modification devices or systems may further include one or more tissue barriers (or “shields”) for further protecting non-target tissues. Such barriers may be slidably coupled with, fixedly coupled with, or separate from the tissue modification devices with which they are used. In various embodiments, a barrier may be delivered between target and non-target tissues before delivering the tissue modification device, may be delivered along with the tissue modification device, or may be delivered after delivery of the tissue modification device but before the device is activated or otherwise used to modify target tissue. Generally, such a barrier may be interposed between the non-target tissue and one or more tissue modification devices to prevent unwanted damage of the non-target tissue.
FIG. 10A shows a distal portion of an introducer device 514 through which a barrier may be introduced. FIGS. 10B and 10C show one embodiment of a barrier 500 partially deployed and in cross-section, respectively. Typically, barrier 500 will have a first, small-profile configuration for delivery to an area near non-target tissue and a second, expanded configuration for protecting the non target tissue. In various embodiments, some of which are described more fully below, barrier 500 may be configured as one piece of super-elastic or shape-memory material, as a scaffold with material draped between the scaffolding, as a series of expandable wires or tubes, as a semicircular stent-like device, as one or more expandable balloons or bladders, as a fan or spring-loaded device, or as any of a number of different devices configured to expand upon release from delivery device 514 to protect tissue. As shown in FIGS. 10B and 10C, barrier 500 may comprise a sheet of material disposed with a first end 502a abutting a second end 502b within introducer device 514 and unfurling upon delivery. In an alternative embodiment, as shown in FIGS. 10D and 10E, opposite ends 522a and 522b of a barrier 520 may overlap in introducer device 514. Generally, barrier 500, 520 may be introduced via introducer device 514 in one embodiment or, alternatively, may be introduced via any of the various means for introducing the tissue modification device, such as those described in conjunction with FIGS. 7A-7S, 8A-8F and 9A-9B. In some embodiments, barrier 500, 520 may be fixedly coupled with or an extension of a tissue modification device. Barrier 500, 520 may also include one or more lumens, rails, passages or the like for passing a guidewire or other guide member, for introducing, removing or exchanging any of a variety of tissue modification, drug delivery, or diagnostic devices, for passing a visualization device, for providing irrigation fluid at the tissue modification site, and or the like. In some embodiments, barrier 500, 520 is advanced over multiple guidewires and the guidewires remain in place during a tissue modification procedure to enhance the stability and/or maintain positioning of barrier 500, 520.
Referring now to FIGS. 11A and 11B, in an alternative embodiment, a powered tissue modification device 1000 suitably includes an elongate shaft 1001 having a proximal portion 1002, a distal portion 1003 and a longitudinal axis 1008, one or more tissue modifying members 1004 coupled with shaft 1001 at or near distal portion 1003, and a handle 1006 coupled with shaft 1001 at or near proximal portion 1002. Optionally, some embodiments may also include one or more power connectors 1010 for connecting device 1000 with one or more power sources. In some embodiments, shaft 1001 has a size and shape that facilitate passage of at least distal portion 1003 into an epidural space of the spine and between target tissue, such as ligamentum flavum, and non-target tissue, such as neural and/or neurovascular tissue. In some embodiments, shaft 1001 may include one or more bends or curves at or near its distal portion 1003 to further facilitate passage and positioning of device 1000. In some embodiments, for example, a bend or curve may facilitate passage of at least part of distal portion 1003 at least partway into an intervertebral foramen.
In some embodiments, as shown in FIG. 11A, distal portion 1003 of device 1000 may be advanced through the skin of the back of a patient, adjacent a spinous process. Distal portion 1003 may then be advanced between the lamina of adjacent vertebral bodies, into the epidural space, and between target and non-target tissues to position tissue modifying member(s) 1004 in a desired location for modifying target tissue. Power may then be provided to activate tissue modifying member(s) 1004 and thus to modify target tissue. A portion of device 1000 adjacent tissue modifying member(s) 1004 may be configured to face non-target tissue while tissue modifying member(s) 1004 face the target tissue, thus preventing unwanted damage or modification of the non-target tissue. In some embodiments, as described more fully above, the portion of device 1000 facing the non-target tissue may be configured to modify the non-target tissue in some way, such as to protect the tissue with a delivered substance, and/or to test the non-target tissue to confirm that it is non-target tissue.
In various embodiments, handle 1006 may have any suitable configuration and features. In some embodiments, handle 1006 includes one or more actuators for activating tissue modifying member(s) 1004. Power connector 1010 may have any suitable configuration and may deliver any suitable type of energy from an external power source (not shown) to device 1000 in various embodiments, such as but not limited to electric, radiofrequency, ultrasound, laser or conductive energy. In alternative embodiments, device 1000 may be battery operated or use any other suitable source of internal power or energy, and such internal energy source may be housed in handle 1006, for example. From whatever source, power is typically transmitted to tissue modifying member(s) 1004 to activate them and thus modify tissue.
With reference now to FIG. 11B, in various embodiments, tissue modification device 1000 may be advanced into a patient using any of a number of suitable techniques and approaches, some of which have been described previously. FIG. 11A illustrates one approach to advancing distal portion 1003 of device 1000 to a position between target and non-target tissue from a contralateral approach, while FIG. 11B illustrates an ipsilateral approach. As shown in FIG. 11B, distal portion 1003 may include two or more bends and/or may be at least partially flexible or steerable to facilitate a desired approach angle, according to various embodiments.
Turning to FIG. 12, in another embodiment a tissue modification device 1020 includes an elongate shaft 1011 having a proximal portion 1012 and a distal portion 1013, one or more tissue modification member(s) 1014, a conductive electrode 1015 coupled with shaft 1011, a handle 1016, a power connector 1030, and multiple additional connection members 1032, 1033. Electrode 1015 may be configured to deliver a non-target frequency and non-target amplitude of electrical current to non-target tissue. The non-target frequency and non-target amplitude may stimulate a response from a neural tissue. In one embodiment, a first connection member 1032 may provide power to electrode 1015, and if non-target-tissue is stimulated by current from the electrode, the observation of this stimulation, as measured by EMG, SSEP or watching for muscular activation, provides evidence that electrode 1015 is adjacent the non-target tissue. A target stimulating electric current may also be delivered through second connection member 1033 to tissue modifying member(s) 1014 (e.g., composed of electrically conductive material) and/or to a target stimulating electrode located adjacent and on the same side of device 1020 as tissue modifying member(s) 1014. For example, if the target simulating electric current is configured with a frequency and amplitude to stimulate a response from neural tissue, the type (e.g., neural, non-neural) of the tissue immediately adjacent tissue modifying member(s) 1014 may be determined based on the tissue response or lack thereof. In one embodiment, device 1020 may be configured to allow for control of the target stimulating electric current and the non-target stimulating electric current. For example, the target stimulating electric current and the non-target stimulating electric current may be sequentially delivered to distal portion 1013 of device 1020 to determine the location of neural tissue prior to activation of tissue modifying member(s) 1014, for example, to help ensure that tissue modifying member(s) 1014 do not damage neural tissue.
In various embodiments, tissue modifying member(s) 1014 may include one or more of a rongeur, a curette, a scalpel, one or more cutting blades, a scissors, a forceps, a probe, a rasp, a file, an abrasive element, one or more small planes, an electrosurgical device, a bipolar electrode, a unipolar electrode, a thermal electrode, a rotary powered mechanical shaver, a reciprocating powered mechanical shaver, a powered mechanical burr, a laser, an ultrasound crystal, a cryogenic probe, a pressurized water jet, or some combination thereof. Some embodiments include one tissue modifying member 1014, while others include multiple tissue modifying members 1014. As is described further below, tissue modifying member(s) 1014 may have any of a number of suitable sizes, shapes and configurations and may move or actuate in any suitable way.
Referring now to FIG. 13A, in an alternative embodiment, a tissue modification device 1040 includes an elongate shaft 1041, one or more tissue modifying member(s) 1044, a handle 1046 and a power connector 1050. Additionally, device 1040 may include a guidewire lumen (not shown) extending through all or part of shaft 1041, which may allow passage of a guidewire 1048 having proximal 1049 and distal 1047 ends therethrough. In one embodiment, for example, guidewire 1048 may extend from a proximal end of shaft 1041 through a distal end of shaft 1041 and out the patient. In some embodiments, as described previously above, anchoring and/or tensioning force may be applied at or near distal end 1047 and/or proximal end 1049 to help urge tissue modifying member(s) 1044 against target tissue.
In the embodiment shown in FIG. 13A, tissue modifying member 1044 is shown having relatively flat configuration. In many of the subsequent embodiments described herein, various embodiments of tissue modifying members are also shown as having flat configurations, primarily for ease of description. In alternative embodiments, however, and with reference now to FIG. 13B, tissue modification device may include a curved and/or flexible tissue modifying member 1045 (or multiple curved and/or flexible members), having a curved/flexible surface for contacting target tissue. Device 1040 may also include a curved and/or flexible shaft 1042. Such curved and/or flexible tissue modifying members 1045 (or tissue modifying surfaces) and shafts 1042 may facilitate tissue modification in some embodiments, in that tissue modifying members 1045 may more readily conform to target tissue. In alternative embodiments, many if not all of the devices described in the present application may have such curved and/or flexible tissue modifying member(s).
Referring now to FIGS. 13C-13E, several alternative embodiments of anchoring members for use with a tissue modification device are shown. FIG. 13C, for example, shows tissue modification device 1040 including a wire anchor 1060 coupled with guidewire 1048. In various embodiments, wire anchor 1060 may be either removably or permanently attached to guidewire 1048 at or near its distal end 1047 to provide anchoring force against the patient's back from outside the patient. Wire anchor 1060 may minimize or prevent guidewire 1048 from moving through the patient's back towards proximal end 1049. In alternative embodiments, additional anchoring and/or tensioning force may be applied to distal end 1047, such as by holding and/or pulling distal end 1047 by hand.
In an alternative embodiment, as shown in FIG. 13D, distal end 1047 of guidewire 1048 may include one or more deployable anchoring members 1062, which may be deployed within the patient to anchor into tissue of the patient's back, such as muscle, bone, ligament or the like. In one embodiment, for example, guidewire 1048 may have one or more lumens (not shown), and anchoring members 1062 may be translated through the lumen(s) to extend out of distal end 1047. When a tissue modification procedure is complete, anchoring members 1062 may be retracted within the lumen(s) so that guidewire 1048 may be more easily removed from the patient.
Referring to FIG. 13E, in another embodiment tissue removal device 1040 may also include one or more proximal shaft anchoring members 1066 and/or one or more proximal guidewire anchoring members 1064. Shaft anchoring member 1066 may, in alternative embodiments, either be coupled with or removably couplable with shaft 1041 to facilitate application of anchoring force. For example, in one embodiment, shaft anchoring member 1066 may abut the patient's back to resist translation of shaft 1041 into the patient.
Proximal guidewire anchoring member 1064 may be included in handle 1046, as shown, or in other embodiments may be located proximal or distal to handle 1046. Guidewire anchoring member 1064 may be used to lock or anchor guidewire 1048 to prevent or minimize its translation into or out of device 1040. This may help facilitate application of tensioning and/or anchoring force via guidewire 1048.
FIGS. 13F and 13G show cross-sectional views of handle 1046 and proximal guidewire anchoring member 1064 taken through line C-C on FIG. 13D. In one embodiment, handle 1046 may include proximal guidewire anchoring member 1064, a tissue modifying drive 1068 in a first lumen, a guidewire 1048 in a guidewire lumen 1070, multiple guiding slots 1074 with corresponding guiding tabs 1075, and one or more lobes 1072. As shown in FIG. 13F, when guidewire anchoring member 1064 is disengaged, guidewire 1048 may freely translate within guidewire lumen 1070, because lobe 1072 does not interfere. As shown in FIG. 13G, when guidewire anchoring member 1064 is engaged, for example by translating and/or rotating guidewire anchoring member 1064 with respect to handle 1046, guidewire 1048 may friction fit (e.g., clamp, pinch) between lobe 1072 of guidewire anchoring member 1064 and the wall of guide wire lumen 1070. Guidewire anchoring member 1064 may then be translated and/or rotated back to the original position (FIG. 13F) to disengage guidewire 1048.
Referring now to FIG. 14, in some embodiments a tissue removal device 1100 may include an elongate shaft 1104 having proximal 1106 and distal 1105 portions, one or more tissue modifying members 1108, a movable handle 1103 coupled with proximal portion 1106, and a power connector 1107. In the embodiment shown, distal portion 1105 is at least partially steerable (shown in FIG. 14 as two, overlapping distal portions), and movable handle 1103 may be used (two-headed, straight arrow) to steer distal portion 1105 while holding shaft 1104 relatively stationary. A steerable distal portion 1105 may enhance the ability of tissue modifying members 1108 to contact and apply force against target tissue. In some embodiments, the location of tissue modifying members 1108 may be adjusted, using steerable distal portion 1105, without significantly moving shaft 1104. In some embodiments, steerable distal portion 1105 may move in multiple directions, such as laterally and up-and-down, relative to the longitudinal axis of shaft 1104. Movable handle 1103 may operate with a piston-like motion, in one embodiment, where a distal portion of handle 1102 is attached to the shaft and a proximal portion handle 1103 is attached to a tensioning member. The tensioning member may translate tension to steerable distal end 1105 when handle 1103 is actuated, which in turn deflects distal end 1105. In various alternative embodiments, any other handle steering mechanisms and/or other steering mechanisms, many of which are known in the art, may be used.
FIGS. 15A and 15B show one embodiment of a tissue modification device 1080, which includes an elongate shaft 1081, one or more tissue modifying members 1082, a handle 1084, a visualization device 1086, an optical cable 1090 and a power connector 1088. Visualization device 1086 may include any suitable device, such as but not limited to an endoscope. An endoscope visualization device may have lenses and/or fiber optics, for example, for delivering light (or other energy) to illuminate the tissue and capturing images. As shown in FIG. 15B, in some embodiments, visualization device 1086 may include one or more image capturing elements 1094 and one or more illuminating elements 1092. Image capturing element 1094 may include, for example, a CCD or CMOS chip, in some embodiments. Illuminating element 1092 may include, for example, one or more light emitting diodes (LEDs) or fiber optics, in some embodiments.
In some embodiments, optical cable 1090 may include fiber optics. Some or all of the fiber optics may comprise or may be coupled with illuminating elements 1092. Alternatively or additionally, some or all of the fiber optics may be connected to a camera (not shown). For example, such a camera may be attached to the proximal end of tissue modification device 1080. Optical cable 1090 may alternatively include one or more electrical wires connected to a power source (e.g., to power LED(s)) and/or an image capturing element 1094. Lenses, fiber optics, LED(s), or combinations thereof may be used for illumination with lenses, fiber optics, CCD, CMOS, or combinations thereof used for image capturing, according to various embodiments.
Referring now to FIG. 16, another embodiment of a tissue modification device 1120 may suitably include an elongate shaft 1132, one or more tissue modifying members 1130, a handle 1124, a visualization device 1122, an optical cable 1128 and a power connector 1126. In this embodiment, visualization device 1122 is located proximal to tissue modifying member(s) 1130 on shaft 1132. In various embodiments, visualization device(s) 1112 may be positioned along shaft 1132 at any desired location.
FIGS. 17A-17E show cross-sectional views of various embodiments of shaft 1132, from the perspective of line A-A in FIG. 16. In the embodiment shown in FIG. 17A, for example, shaft 1132 may include a tissue modifying drive 1134 within a tissue modifying drive lumen 1140, and a guidewire 1136 within a guidewire lumen 1138. Tissue modifying drive 1134 may be configured to translate or rotate with respect to tissue modifying drive lumen 1140. Examples of tissue modifying drives 1134 include, but are not limited to, a drive shaft, one or more conductive wires, one or more optical fibers, or the like. Various embodiments may also include a motor, which may be located in the handle of the device, near the device distal end, in a separate drive apparatus, or the like.
In an alternative embodiment, as shown in FIG. 17B, shaft 1132 may include tissue modifying drive 1134 within tissue modifying drive lumen 1140, guidewire 1136 within guidewire lumen 1138, conductive elements 1146 within a visualization lumen 1144, and suction/irrigation lumen 1142. Suction/irrigation lumen 1142 may be used, for example, to deliver gas, fluid or pushable solids (e.g., granular solids) from outside the patient to the distal end of the device or to aspirate gas, fluids, tissue and/or other material from the targeted tissue region to the outside of the patient. Suction/irrigation lumen 1142 may also be used, in some embodiments, to slidably pass instruments, such as a long flexible needle or biopsy forceps. Visualization lumen 1144, in some embodiments, may be configured to receive conductive elements 1146, such as elements to power LEDs at the distal end of the device, and/or to carry the signal from a CCD or CMOS chip located at the distal end of the device that has captured a visual image and converted it into an electronic signal to a display device located outside the patient.
In yet another alternative embodiment, shown in FIG. 17C, shaft 1132 may include tissue modifying drive 1134 within tissue modifying drive lumen 1140, conductive elements and/or fiber optics 1152 within visualization lumen 1144, and separate suction 1150 and irrigation 1148 lumens. Suction lumen 1150 and irrigation lumen 1148 may be used, in some embodiments, to simultaneously or sequentially deliver and remove gases, fluids and/or pushable solids to and from the distal end of a tissue modification device. Delivery and removal of gases, fluids and/or pushable solids may help clear detached and/or non-detached target tissue and other debris from the treatment site and/or maintain a clear visualization of the target and non-target tissue via the visualization element.
In another embodiment, illustrated in FIG. 17D, fiber optics 1152 may be disposed within a hollow shaft 1132, in between various lumens 1148, 1150, 1144, 1140. Alternatively, fiber optics 1152 may be replaced with electrical conductors in other embodiments. Fiber optics 1152 may deliver light to illuminate the target tissue and/or deliver light from the tissue to a viewing device. Visualization lumen 1144, in such an embodiment, may transport light or electrical signals in proximal and/or distal directions.
In yet another alternative embodiment, as in FIG. 17E, shaft 1132 may include a steering actuator 1154 within a steering lumen 1156. Steering actuator 1154 may be used, for example, to help steer a distal portion of a tissue modification device, as described in further detail above.
FIG. 18 is an end-on cross-sectional view of tissue modification device 1120 of FIG. 16, shown from the perspective of line B-B. In this embodiment, visualization device 1122 and illuminating elements 1158 are located proximal to tissue modifying member 1130. In the embodiment shown, tissue modifying member 1130 includes a rotating disc mounted on a post in a bearing 1160, with multiple raised cutting edges 1131 on the disc. Two suction/irrigation lumens 1142 allow for introduction and suction of gas, fluid and/or pushable solids from an area of tissue modification.
FIGS. 19-40F illustrate a number of embodiments of a distal end of a tissue modification device having various different tissue modifying members. Referring to FIG. 19, in one embodiment, a tissue modification device 1170 may include multiple tissue modifying members 1172, each including a cup 1174 attached to a drive shaft 1173 and having a cutting edge 1175. Tissue modifying members are located within an open chamber 1176 formed by multiple walls 1178, 1180, 1182, 1184, 1186. Cups 1174 may be rotated and/or translated to cut target tissue disposed in open chamber 1176, as shown by the curved and straight arrows.
FIG. 19A illustrates an alternative embodiment in which a tissue modification device 1170a may include a shaft 1171, which is curved and/or flexible along at least part of its length, and a tissue modifying portion 1177, which is also curved and/or flexible. Tissue modifying portion 1177 may include curved and/or flexible shafts 1173a, and cups 1174a, similar to those shown in FIG. 19. As mentioned previously, many of the embodiments described herein may have either flat/straight tissue modifying members/surfaces or curved and/or flexible tissue modifying members/surfaces, according to various embodiments. Therefore, although many of the following embodiments of tissue modifying members are shown and described as having generally flat configurations, in alternative embodiments, many if not all such tissue modifying members may have curved and/or flexible configurations instead.
In an alternative embodiment, shown in FIG. 20, a tissue modification device 1190 may include multiple tissue modification members 1192, each comprising a hollow tube 1194 with a cutting edge 1193. In one embodiment, tubes 1194 may be rotated and translated to cut tissue. Tubes 1194 may also be used for suction and/or irrigation in some embodiments.
FIG. 21 shows another alternative embodiment, in which a tissue modification device 1200 includes a tissue modifying member 1202 comprising a disc and multiple raised cups 1204, each cup having a cutting edge 1205, and the disc being mounted on a drive shaft 1206. In one embodiment, tissue modifying member may oscillate by moving shaft 1206 back and forth and/or may rotate by rotating the disc around an axis.
In another embodiment, as in FIG. 22, a tissue modification device 1210 may include two rotating tissue modification members 1212a, 1212b, each comprising a disc with raised cutting members. The discs may rotate in the same directions or opposite directions in various embodiments. Rotating members 1212a, 1212b in opposite directions may help balance forces between the two members 1212a, 1212b and target tissue, thereby helping stabilize tissue modification device 1210 and enhance tissue modification procedures.
FIG. 23 illustrates that, in some embodiments, a tissue modifying member 1224 of a tissue modification device 1220 may be angled relative to a longitudinal axis of a distal portion 1126 of a shaft 1222. Angling tissue modifying member 1224 away from the long axis of distal portion 1126 may allow tissue modifying member 1224 to extend out of a an open chamber or window, for example, to facilitate tissue in various embodiments. Angling tissue modifying member 1224 may also enhance contact of tissue modifying member 1224 with target tissue, thus enhancing tissue modification.
In another alternative embodiment, as in FIG. 24, a tissue modification device 1230 may include a tissue modification member 1234 that extends out of a distal opening 1236 at the distal end of a shaft 1232. In some embodiments, tissue modification member 1234 may be moved back and forth to be housed within or to extend out of distal opening 1236. In other embodiments, tissue modification member 1234 may be fixed in relation to opening 1236.
FIG. 25 shows another embodiment of a tissue modification device 1240, which includes tissue modifying members 1242, each including a rotating shaft 1244, 1246 and a helical cutting blade 1248. Device 1240 also may include one or more irrigation ports 1250 and one or more suction ports 1252. In various embodiments, cutting blades 1248 may be configured to remove both hard and/or soft tissue. Cutting blades 1248 may also be configured to transport separated tissue proximally toward and/or into the shaft of device 1240, and/or suction port 1252, so that such tissue may be removed from the patient. Rotating shafts 1244 may be configured to rotate in opposite directions, in some embodiments, thus helping balance forces exerted by tissue modifying members 1242 on target tissues.
In yet another embodiment, shown in FIG. 26, a tissue modification device 1260 may include a tissue modifying member 1262 comprising a belt 1266, mounted on rotating rollers 1264 and carrying multiple raised abrasive members 1268. Rollers 1264 may be activated to rotate, thus causing belt 1266 to move, and thus causing abrasive members 1268 to abrade target tissue.
In a similar alternative embodiment, shown in FIG. 27, a tissue removal device 1270 may include a tissue modifying member 1272 comprising a belt 1276, mounted on rotating rollers 1278 and carrying multiple raised cutting members 1274. Rollers 1278 may be activated to rotate, thus causing belt 1276 to move, and thus causing cutting members 1274 to cut target tissue.
Referring to FIG. 28, in another alternative embodiment, a tissue removal device 1280 may include a tissue modifying member 1286 comprising one or more wires that move along multiple transverse guide rails 1282, 1284. In one embodiment, tissue modifying member 1286 may move laterally along guide rails 1282, 1284 and may also translate over guide rails 1282, 1284. In various embodiments, the tissue modifying member(s) 1286 (i.e., the wire(s)) may translate, rotate, reciprocate and/or oscillate. In some embodiments, the wire(s) may be coated (e.g., on the outer surface) with an abrasive material, and/or have a high friction outer texture. In some embodiments, the wires may be coupled to an energy (e.g., RF current, thermal) generator. In alternative embodiments, wires may be solely at or within the shaft distal portion or may extend from the shaft distal end to a more proximal location along shaft.
FIG. 29 illustrates another embodiment of a tissue modification device 1290, in which a tissue modifying member 1292 is coupled with rotating drive post 1294 and two free posts 1296, 1298. Drive post 1294 is coupled with a drive shaft 1302, which turns drive post 1294, thus translating tissue modifying member 1292 to modify tissue. Tissue modifying member 1292 may be elevated above a floor 1300 of the device shaft, so as to more easily contact target tissue. In various embodiments, tissue modifying member 1292 comprises a cutting wire or abrasive wire and may be translated either in one direction or in both directions. In some embodiments, drive shaft 1302 may be advanced and retracted to further move and/or change the configuration of tissue modifying member 1292.
Referring now to FIGS. 30A-30C, in another embodiment, a tissue modification device 1310 may include a tissue modifying member 1312 comprising a movable platform with an abrasive surface and coupled with a drive shaft 1314 extending out of a distal opening 1316. As shown in the various figures, in some embodiments tissue modifying member 1312 may move laterally (FIG. 30A), may translate back and forth (FIG. 30B) and/or may vibrate (FIG. 30C).
In yet another embodiment, as in FIG. 31, a tissue modification device 1320 may include a tissue modification member 1322 comprising an oval or round platform with an abrasive surface and coupled with a drive shaft 1324 extending out of a distal opening 1326. In such an embodiment, tissue modifying member 1322 may be made to rotate or move in a circular pattern, as well as translate, move laterally, oscillate and/or vibrate according to various embodiments.
Referring to FIG. 32, in another embodiment a tissue modification device 1330 includes multiple tissue modifying members 1332, each including a movable platform 1333 with an abrasive surface attached to a drive shaft 1334. Tissue modifying members may move back and forth relative to one another and to the device shaft in any suitable pattern. Moving tissue modifying members 1332 back and forth relative to one another may help them apply tensioning forces to target tissue, thereby enhancing the ability of tissue modifying members 1332 to cut, shear, tear and/or otherwise modify target tissues.
As shown in FIG. 33, in another alternative embodiment, a tissue modification device 1340 may suitably include tissue modifying members comprising one or more blades, such as a distal blade 1344a and a proximal blade 1344b, each having a cutting edge 1345a, 1345b. In the embodiment shown, proximal blade 1344b is movable and may translated distally toward the opposing distal blade 1344a. In alternative embodiments, distal blade 1344a may be movable or both blades 1344a, 1344b may be movable. Alternative embodiments may include one movable blade, more than two movable blades facing in one direction, more that two movable blades facing in different directions, a movable blade and a backstop against which the blade may be driven, or any other suitable combination of movable and/or immobile blades. Furthermore, any blade of any given embodiment may have any suitable shape, size and overall configuration. In some embodiments, blades may be flat, while in others they may be curved, squared off, ridged, bent, serrated or the like. Blades may be long or short, multiple blades may be aligned closely one after the other, such as in a typical multi-blade razor used for shaving a face, multiple blades may be disposed apart from one another by several millimeters or even centimeters, and/or the like. Blades may have any suitable amount of sharpness or dullness, and in some embodiment a combination of sharper and duller blades may be used. Therefore, although exemplary embodiments of blades are described in detail above and below, any other suitable blades or combinations of blades may be substituted in various embodiments, without departing from the scope of the present invention.
Blades 1344a, 1344b, or any other blades described in alternative embodiments herein, may be fabricated from metals, polymers, ceramics, any other suitable material or combination of materials. According to various embodiments, suitable metals for blades may include, but are not limited to, stainless steel, nickel-titanium alloy, or cobalt-chromium alloy, for example, ElgiloyTM (Elgin Specialty Metals, Elgin, Ill., USA), ConichromeTM (Carpenter Technology, Reading, Pa., USA), or PhynoxTM (Imphy SA, Paris, France). Polymer materials include nylon, polyester, DacronTM, polyethylene, acetal, DelrinTM (DuPont), polycarbonate, nylon, polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). In some embodiments where polymers are used, such polymers may be glass-filled or carbon-filled to add strength and stiffness. Ceramics may include, but are not limited to, aluminas, zirconias, and carbides. Blades may be manufactured using skills known in the art, for example, metal injection molding (MIM), CNC machining, injection molding, grinding, EDM, sheet metal bending, etching, or the like. Other portions of a tissue modification device, such as a cover over one or more blades or other features, may be made of any suitable material now known or hereafter discovered. A blade cover, for example, may be fabricated in various embodiments of one or more polymeric materials, such as nylon, silicone, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polytetrafluoroethylene (PTFE), polyurethane (Tecothane,), Pebax (co, USA), polycarbonate, Delrin (co, USA), high-density polyethylene (HDPE), low-density polyethylene (LDPE), HMWPE, UHMWPE, or the like.
Referring now to FIG. 34A, in one embodiment a tissue modification device 1350 may have a substantially cylindrical, circular, or otherwise curved shaft 1352 as well as one or more substantially cylindrical, circular, or otherwise curved blades 1354. In the embodiment shown, blade 1354 protrudes out of a window 1358 of shaft 1352. When blade 1354 is moved proximally (arrow), its cutting edge 1356 moves toward and perhaps engages with an opposing cutting edge 1356 of shaft 1352.
In an alternative embodiment, as in FIG. 34B, a tissue modification device 1360 may have a substantially cylindrical, circular, or otherwise curved shaft 1362 as well as one or more substantially cylindrical, circular, or otherwise curved blades 1364. In the embodiment shown, blade 1364 protrudes out of a window 1368 of shaft 1362. Blade 1364 may be rotated (arrows), to cause its cutting edges 1366 cut target tissue. In some embodiments, one or more curved blades 1364 may be translated as well as rotated. In either of the embodiments shown in FIGS. 34A and 34B, cut target tissue may optionally be removed through the inside of curved shaft 1352 or curved blade 1364.
Referring now to FIGS. 35A and 35B, in some embodiments, a tissue modification device may include one or more anchoring members 1374 coupled with a distal shaft portion 1370 of the device. In various embodiments, any of a number of suitable anchoring members may be used. Some embodiments of anchoring members have been previously described above, and others will be described further below. In one embodiment, for example, anchoring members 1374 may comprise multiple needles, as shown in FIGS. 35A and 35B. Needles 1374 may act not only to anchor distal shaft portion 1370 to tissue, but may also change one or more characteristics of the tissue. For example, in some embodiments, inserting multiple needles into tissue may stiffen the tissue and thus enhance the ability of one or more tissue modifying members 1372 to cut or otherwise modify the tissue. In one embodiment, anchoring members/needles 1374 may be deployable out of distal shaft portion 1370 (arrow), such that needles 1374 are retracted during delivery of the device into the patient and then deployed into the target tissue when in a desired position. In various embodiments, anchoring members/needles 1374 may extend out of distal shaft portion 1370 in an orientation substantially perpendicular to the longitudinal axis of distal shaft portion 1370 or in any other suitable orientation relative to distal shaft portion 1370. or otherwise non-parallel to the longitudinal axis. During use, the tissue stiffening projections can extend into the target tissue. Needles 1374 will typically have a modulus of elasticity greater than the modulus of elasticity of the target tissue, and thus may stiffen (i.e., increase the effective modulus of elasticity) of the target tissue.
In the embodiment shown in FIGS. 35A and 35B, as well as in any alternative embodiments described herein, one or more members such as tissue anchoring members/needles 1374 may be used to modify tissue in any of a number of suitable ways. For example, in some embodiments, energy may be transmitted to one or more tissue anchoring members/needles 1374 to cool, heat or otherwise transmit energy to the tissue. Such cooling or heating, for example, may further change the stiffness or consistency of the tissue, thus facilitating tissue modification by one or more tissue modifying members. In one embodiment, for example, it may be advantageous to cool or even freeze tissue to increase its stiffness so that it can be more easily cut or abraded. For example, in some embodiments, a cryogenic fluid may be delivered via an irrigation lumen and/or suction/irrigation lumen to directly reduce the temperature of the anchoring members 1374 or to separately cool the target tissue. Any other suitable change may alternatively be made to tissue to enhance a tissue modification procedure according to various embodiments.
As shown in FIG. 35B, when anchoring members 1374 are in place within target tissue, tissue modifying member 1372 (a blade in the embodiment shown) may be translated out of distal shaft portion to cut or otherwise modify tissue. Tissue modifying member 1372 may advance out of distal shaft portion 1370 in a direction perpendicular or otherwise non-parallel to anchoring members 1374. In some embodiments, anchoring members/needles 1374 may retain target tissue after cutting, so that it may be removed from the patient.
FIGS. 36A and 36B illustrate an alternative embodiment a tissue stiffening probe 1382 extends out of a distal shaft portion 1380 (FIG. 36A) and then breaks into multiple tissue stiffening inserts 1386 (FIG. 36B) to stiffen target tissue before it is modified by a tissue modifying member 1384. Alternatively, multiple tissue stiffening inserts 1386 may be delivered directly into the tissue. In some embodiments, inserts 1386 may be made from a bioresorbable material, so that if one or more inserts are left in the patient, they will harmlessly resorb in the patient's body.
In yet another embodiment, shown in FIGS. 37A and 37B, a tissue modification device 1390 includes multiple deployable tissue anchoring members 1392 and a tissue modifying blade 1396 that translates through a blade lumen 1394. Tissue anchoring members 1392 may have a curved or circular configuration upon being deployed from tissue modification device 1390, and in some embodiments they may serve the dual function of anchoring to tissue and stiffening tissue.
With reference now to FIG. 38A, an end-on view of one embodiment of a tissue modification device 1400 shows that anchoring members 1406 may alternatively comprise one or more deployable support members, which may be extended laterally out of a distal shaft portion 1402 to anchor in tissue and support distal shaft portion 1402 and a tissue modifying member 1404. Any desired number, size, shape and configuration of lateral anchoring members 1406 may be used in various embodiments.
FIG. 38B shows an alternative embodiment in which a tissue modification device 1410 includes anchoring members 1416, which extend laterally and inferiorly from a distal shaft portion 1412 to support distal shaft portion 1412 and tissue modifying member 1414.
In yet another embodiment, as shown in FIG. 38C, an inflatable balloon 1426 may be included on a distal shaft portion 1422 of a tissue modification device 1420 to support distal shaft portion 1422 and tissue modifying member 1424.
Referring now to FIGS. 39A-39D, in another alternative embodiment, a tissue modification device 1430 may suitably include a shaft 1432 and a semicircular tissue modifying member 1434. Tissue modifying member 1434 may include multiple cup-shaped blades 1435, each having a cutting edge 1436, and may rotate about a central axle 1440 that defines a central axis of rotation 1438. In some embodiments, as shown in FIG. 39B, tissue modifying member 1434 may be hollow and may include a chamber 1442 which may collect cut tissue for removal from the patient. Cups 1435 may be in fluid communication with chamber 1442 such that at least some of the tissue removed by cups 1435 enters chamber 1442. Suction may be applied to enhance the capture of tissue in chamber 1442 and/or to remove tissue from chamber 1442 proximally through shaft 1432.
Each cup 1435 may be spaced apart from adjacent cups 1435 at regular angle intervals, for example, in longitudinal and/or latitudinal direction around tissue modifying member 1434. Cups 1434 may be disposed on all or part (FIGS. 39C and 39D) of the perimeter of tissue modifying member 1434. Tissue modifying member 1434 may rotate, in various embodiments, either clockwise, counterclockwise or both. In some embodiments, tissue modifying member 1434 may have clockwise and/or counterclockwise rotational limits. For example, such rotational limits may comprise from about −180° to about 180°, or alternatively from about −90° to about 90°, or alternatively from about −45° to about 45°. In some embodiments, tissue modification device 1430 may be counterbalanced (e.g., to minimize vibrations caused by the oscillating or otherwise rotating tissue modifying member 1434 during use). For example, shaft 1432 may comprise an offset-weighted rotating balance shaft.
Referring now to FIGS. 40A-40F, another alternative embodiment of a tissue modification device 1440 may include a shaft 1442, and a tissue modifying member 1444 including multiple cutting members 1445. (In alternative embodiments, tissue modifying member 1444 may include an abrasive surface in place of cutting members 1445.) As shown in FIGS. 40B and 40C, tissue modifying member 1444 may include a platform 1448, multiple cutting members 1445, an axle 1456 defining an axis of rotation 1458, a bottom plate 1450, a drive groove 1452, a cross beam 1454, and a base plate 1460. Device 1440 may further include a tissue modifying drive shaft 1462. Base plate 1460 may be rigidly attached to a mount 1464 (FIG. 40C). Platform 1448 may be integrated with and/or attached to bottom plate 1450 at cross beam 1454 or, in an alternative embodiment, at a center shaft (not shown). Cross beam 1454 may include a stress relief channel 1466 (FIG. 40C). Mount 1464 may be rotatably attached to stress relief channel 1466. For example, mount 1464 may have one or more protruding beams that may extend into stress relief channel 1466. Mount 1464 may be on one or both sides of the tissue modifying member 1444. Mount 1464 may be biased with respect to stress relief channel 1466, for example, to force cross beam 1454 to a configuration (e.g., perpendicular) with respect to base plate 1460 and bottom plate 1450, as shown in FIGS. 40B and 40C.
In various embodiments, platform 1448 may be flexibly and/or rigidly integrated and/or attached to cross beam 1454. Bottom plate 1450 may be flexibly and/or rigidly integrated and/or attached to cross beam 1454. Base plate 1460 and/or bottom plate 1450 and/or cross beam 1454 may be attached and/or integrated to drive shaft 1462. For example, the tissue modifying member 1444 may include a drive groove, and the drive groove may be configured to receive drive shaft 1462.
FIGS. 40D-40F demonstrate that tissue modifying member 1444 may flex to accommodate and more effectively modify target tissue from a number of orientations. FIG. 40D illustrates that the target tissue may be proximal to rotational axis 1458. Top plate 1448 may rotate with respect to bottom plate 1450. Additionally, all or part of bottom plate 1450 may rotate with respect to base plate 1460. Top plate 1448 may rotate passively (e.g., forced by pressure against the target tissue) or actively (e.g., driven by a motor or electrical current).
FIG. 40E illustrates that the target tissue can be substantially aligned with rotational axis 1458, while FIG. 40F illustrates that the target tissue can be distal to rotational axis 1458.
Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. For example, in many of the embodiments described above, one or more abrasive tissue modifying members may be substituted for one or more bladed tissue modifying members or vice versa. These an many other modifications may be made to many of the described embodiments. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.
In FIG. 41, straight wire or needle 4 is driven through curved needle 16 disposed in working channel 50 of double barrel epidural needle. This straight wire or needle 4 is advanced until it has penetrated through the skin and out of the patient's body. The straight wire preferably has a sharp tip. In FIG. 42, curved needle 16 is withdrawn from working channel 50, leaving straight wire or needle 4 in place. Then, as seen in FIG. 45, the epidural needle and working channel may be withdrawn from the patient, or, in an alternative embodiment, when using a detectable working channel 50, the working channel alone may be withdrawn from the patient, leaving straight wire 4 in place. In FIG. 44, straight wire 4 is hooked to abrasion device 14 and/or the abrasion device's protective sleeve 6. In FIG. 47, the abrasion device 14 and/or the device's protective sleeve are pulled into position by wire 4 as the wire is removed. In FIG. 48, wire 4 has been completely removed, and the abrasion device 14 and its protective sleeve 6 are properly positioned for tissue resection, anterior to the facet 12 and ligamentum flavum 10.

## Claims

1. A device for modifying spinal tissue, the device comprising:
an elongate shaft having a flexible distal portion that is configured to be passed into an epidural space of the spine and between target and non-target tissues;
a movable blade, connected to one side of the flexible distal portion of the elongate shaft proximal to the distal end of the flexible distal portion of the elongate shaft;
a protective surface on one side of the flexible distal portion of the elongate shaft opposite and behind the movable blade that prevents non-target tissues from being cut by the blade;
a guidewire coupling member at the distal portion of the shaft and configured to facilitate application of a distal pulling force to urge the movable blade against the target tissue, wherein the guidewire coupling member is configured to grasp the end of a guidewire to the distal end portion of the tissue modification device;
a handle at the proximal end of the shaft, wherein the handle includes an actuator to actuate movement of the movable blade;
a drive shaft disposed along the elongate shaft having a proximal end coupled to the handle and a distal end coupled to the movable blade, wherein the drive shaft is configured to move the movable blade to cut a target tissue without significantly translating the elongate shaft proximally or distally.

2. A device as in claim 1, wherein the distal portion of the shaft has a width of not more than 7 mm.

3. A device as in claim 1, wherein the distal portion of the shaft has a height of not more than 2 mm.

4. A device as in claim 1, wherein the shaft includes at least one bend at or near the distal portion.

5. A device as in claim 1, further comprising a guidewire coupled with the guidewire coupling member extending from the distal portion of the shaft.

6. A device as in claim 1, further comprising an anchoring member for anchoring the distal portion of the device from outside of a patient.

7. A device as in claim 1, wherein the movable blade is disposed along a length of the distal portion measuring no longer than 3 cm.

8. A device as in claim 1, further comprising a deployable anchoring member for anchoring the device to tissue.

9. A device as in claim 1, further comprising at least one barrier device slidably coupled with the shaft for preventing unwanted damage to nearby tissues during a tissue modification procedure.

10. A device as in claim 1, wherein the shaft includes a hollow chamber at or near its distal end for collecting removed tissue.

11. A system for treating spinal stenosis, the system comprising:
a tissue modification device, comprising:
an elongate body having a flexible distal portion configured for passing into an epidural space and at least partway into an intervertebral foramen;
a guidewire coupling member disposed at the distal portion, wherein the guidewire coupling member is configured to facilitate application of a distal pulling force to urge the flexible distal portion against a target tissue, wherein the guidewire coupling member is configured to grasp the end of a guidewire to the distal end portion of the tissue modification device;
a tissue modifying member connected to one side of the flexible distal portion of the elongate body proximal to the distal end of the distal portion;
a protective surface on one side of the flexible distal portion of the elongate body opposite and behind the tissue modifying member that prevents non-target tissues from being modified by the tissue modification member;
a proximal handle coupled with a proximal portion of the elongate body;
a drive shaft disposed along the elongate body having a proximal end coupled to the handle and a distal end coupled with the tissue modifying member to activate the tissue modifying member; and

a guidewire couplable with the guidewire coupling member.

12. The device of claim 11, further comprising a power transmission member coupled with the drive member to deliver power to the drive member.

13. A system as in claim 12, wherein the power transmission is disposed in the proximal handle.

14. The system as in claim 11, further comprising a distal handle couplable with the guidewire.

15. The system as in claim 11, wherein the tissue modification device further comprises one or more tissue protective surfaces disposed along the distal portion adjacent the tissue modifying member.

16. A system for treating spinal stenosis, the system comprising:
a tissue modification device, comprising:
an elongate body having a flexible distal portion configured for passing into an epidural space and at least partway into an intervertebral foramen;
a guidewire coupling member disposed at the distal portion, wherein the guidewire coupling member is configured to facilitate application of a distal pulling force to urge the flexible distal portion against a target tissue;
a tissue modifying member connected to one side of the flexible distal portion of the elongate body proximal to the distal end of the distal portion;
a protective surface on one side of the flexible distal portion of the elongate body opposite and behind the tissue modifying member that prevents non-target tissues from being modified by the tissue modification member;
a proximal handle coupled with a proximal portion of the elongate body;
a drive shaft disposed along the elongate body having a proximal end coupled to the handle and a distal end coupled with the tissue modifying member to activate the tissue modifying member;

a guidewire couplable with the guidewire coupling member; and
a distal handle couplable with the guidewire.

17. A device for modifying spinal tissue, the device comprising:
an elongate shaft having a flexible distal portion that is configured to be passed into an epidural space of the spine and between target and non-target tissues;
a movable blade, connected to one side of the flexible distal portion of the elongate shaft proximal to the distal end of the flexible distal portion of the elongate shaft;
a protective surface on one side of the flexible distal portion of the elongate shaft opposite and behind the movable blade that prevents non-target tissues from being cut by the blade;
a guidewire coupling member at the distal end of the flexible distal portion of the elongate shaft and configured to facilitate application of a pulling force in the distal direction to urge the movable blade against the target tissue;
a handle at the proximal end of the shaft, wherein the handle includes an actuator to actuate movement of the movable blade;
a drive shaft disposed along the elongate shaft having a proximal end coupled to the handle and a distal end coupled to the movable blade, wherein the drive shaft is configured to move the movable blade to cut a target tissue without significantly translating the elongate shaft proximally or distally.

18. The device of claim 17, wherein the flexible distal portion of the device comprises a tapered body configured to be passed out of the patient while the movable blade member remains between the target and non-target tissues.

19. The device of claim 17, wherein the guidewire coupling member comprises a lumen passing through the elongate body.

20. A system for treating spinal stenosis, the system comprising:
a tissue modification device, comprising:
an elongate body having a flexible distal portion configured for passing into an epidural space and at least partway into an intervertebral foramen;
a guidewire coupling member disposed at the distal portion, wherein the guidewire coupling member is configured to facilitate application of a pulling force in the distal direction to urge the flexible distal portion against a target tissue;
a tissue modifying member connected to one side of the flexible distal portion of the elongate body proximal to the distal end of the distal portion;
a protective surface on one side of the flexible distal portion of the elongate body opposite and behind the tissue modifying member that prevents non-target tissues from being modified by the tissue modification member;
a proximal handle coupled with a proximal portion of the elongate body;
a drive shaft disposed along the elongate body having a proximal end coupled to the handle and a distal end coupled with the tissue modifying member to activate the tissue modifying member; and

a guidewire couplable with the guidewire coupling member such that it extends distally from the distal portion of the shaft.

21. The device of claim 20, wherein the flexible distal portion of the device comprises a tapered body configured to be passed out of the patient while the tissue modifying member remains between the target and non-target tissues.

22. The device of claim 20, wherein the guidewire coupling member comprises a lumen passing through the elongate body.