Abstract:
A spinal disc implant delivery device includes a blocking component having opposed distal and proximal ends. The proximal end of the blocking component includes an anchor member configured and adapted for movement between an undeployed position in which the anchor member can pass into and out of an opening in a disc annulus, and a deployed position in which the anchor member anchors the blocking component to the opening of the disc annulus. In the deployed position, the anchor member is configured to prevent extrusion of implant material from the opening of the disc annuls. An implant delivery needle is located radially within the blocking component and has opposed proximal and distal ends. The needle is configured to deliver implant material from the distal end thereof to an interior of a disc annulus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 61/248,220, filed Oct. 2, 2009, which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to methods and devices for treating spinal conditions, and more particularly, to methods and devices for modifying intervertebral disc tissue. 
     2. Description of Related Art 
     A variety of devices and methods are known in the art for treating pain in the human spine. Of such devices, many are directed to relieving pain arising from intervertebral disc abnormalities. Intervertebral disc abnormalities are common in the population and cause considerable pain, particularly if they affect adjacent nerves. Disc abnormalities result from trauma, wear, metabolic disorders and the aging process and include degenerative discs, localized tears or fissures in the annulus fibrosus, localized disc herniations with contained or escaped extrusions, and chronic, circumferential bulging discs. Disc fissures occur as a degeneration of fibrous components of the annulus fibrosus. Rather minor activities such as sneezing, bending or simple attrition can tear degenerated annulus fibers and create a fissure. The fissures may be further complicated by extrusion of nucleus pulposus material into or beyond the annulus fibrosus. Difficulties can still present even when there is no visible extrusion, due to biochemicals within the disc irritating surrounding structures and nerves. 
     A contained disc herniation is not associated with free nucleus fragments migrating to the spinal canal. However, a contained disc herniation can still protrude and irritate surrounding structures, for example by applying pressure to spinal nerves. Escaped nucleus pulposus can chemically irritate neural structures. Current treatment methods include reduction of pressure on the annulus by removing some of the interior nucleus pulposus material by percutaneous nucleotomy. Complications include disc space infection, nerve root injury, hematoma formation, instability of the adjacent vertebrae and collapse of the disc from decrease in height. It has been proposed to treat weakening due to nucleus pulposus deficiency by inserting preformed hydrogel implants. 
     More recently, delivery of in situ curing liquids to form a solid prosthetic in the nucleus of a disc have been disclosed. The fluid form of these implants enables access to the spine in a minimally invasive manner, and includes procedures for restoring structural integrity to vertebral bodies. There are a variety of injectable biomaterials known in the art including: cross-linkable silk elastin copolymer, protein hydrogel, polyurethane-filled balloons, collagen-PEG, chitosan, and other polymers. 
     Delivery of an in situ forming prosthetic to the nuclear space requires constructing a passageway into the nucleus and removal of the nucleus fibrosus, in total or in part. The passageway is usually made through the annulus, especially when part of the annulus needs to be removed to correct a pathological condition. Whether the passageway is through the annulus or elsewhere, for example, through the vertebral body, there is a risk of the formed nucleus prosthetic extruding out through the passageway into which it is introduced. Nucleus prosthetic extrusion can affect the surrounding nerves adversely. Methods of blocking a passageway made through the annulus include, for example, enclosing the prosthetic entirely inside of an enveloping sheath. Still other methods of preventing nuclear prosthetic extrusion include delivering a preformed prosthetic in a reduced state, which when introduced into the body increases in volume. 
     U.S. Patent Application Publication No. 2009/0024107, to Wilson et al., describes a device for blocking a passageway made through the annulus to prevent extrusion of implant material. A catheter balloon is introduced into the annulus opening flush with the interior space of the annulus while implant material is injected through an axially located catheter running through the interior of the catheter balloon. This technique can block extrusion of the implant material through the opening of the annulus, however it does not provide a positive anchor of the delivery apparatus. Therefore, it is necessary for the user of the device to devote constant attention to prevent accidental removal of the catheter balloon during the procedure. If the device is accidentally removed from the annulus during the procedure, not only will there be difficulty in repositioning the device at the opening of the annulus, but implant material can freely exit the opening of the annulus, giving rise to further complications. 
     This typically means that one hand of the user is constantly tied up just to maintain the position of the device. This is a problem, when for example, two hands are required to attach a syringe of implant material to the applicator during a procedure. Even when the user manages to maintain the position of the device using one hand, difficulties can arise if, for example, the user&#39;s other hand is also tied up with actuating the injection of the implant. In such situations, the user will not have any hand free for other necessary tasks that may arise during the procedure. 
     The conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there still remains a continued need in the art for methods and devices that can provide improved blocking of disc implant material from extrusion out the opening of a vertebral disc annulus while providing improved anchoring of a delivery device to the opening of the annulus. There also remains a need in the art for such methods and devices that are easy to make and use. The present invention provides a solution for these problems. 
     SUMMARY OF THE INVENTION 
     The subject invention is directed to a new and useful spinal disc implant delivery device. The device includes a blocking component having opposed distal and proximal ends. The proximal end of the blocking component includes an anchor member configured and adapted for movement between an undeployed position in which the anchor member can pass into and out of an opening in a disc annulus, and a deployed position in which the anchor member anchors the blocking component to the opening of the disc annulus. In the deployed position, the anchor member is configured to prevent extrusion of implant material from the opening of the disc annuls. An implant delivery needle is located radially within the blocking component and has opposed proximal and distal ends. The needle is configured to deliver implant material from the distal end thereof to an interior of a disc annulus. 
     In accordance with certain embodiments, the implant delivery needle is moveable relative to the blocking component in an axial direction. A pressure sensor can be mounted to at least one of the blocking component and the implant delivery needle, or any other suitable location for monitoring pressure within a disc annulus during an implant procedure. The anchor member can include a mesh portion that is biased toward the deployed position. The mesh portion can include a membrane lining to prevent extrusion of implant material through the mesh portion. 
     In certain embodiments, the anchor member includes a catheter balloon configured and adapted to inflate into the deployed position within an interior of a disc annulus to prevent withdrawal of the blocking component from the disc annulus. The blocking component can include a catheter having opposed proximal and distal ends, wherein the catheter balloon is attached to the catheter by a ferrule mounted to the catheter. The ferrule can be mounted at the distal end of the catheter. It is also contemplated that the catheter balloon can include a flexible tube with a distal end thereof folded radially inward and overlapping a radially outward portion of the flexible tube, with the distal end of the flexible tube being mounted to the catheter proximate the distal end of the catheter. 
     The invention also provides a method of delivering a spinal disc implant. The method includes introducing a blocking device into an opening of a spinal disc annulus, the blocking device including an anchor member proximate a distal end thereof. A step is included for extending the anchor member of the blocking device into an interior of the disc annulus. The method also includes actuating the anchor member from an undeployed position in which the anchor member can pass into and out of an opening in the disc annulus, to a deployed position in which the anchor member anchors the blocking component to the interior of the disc annulus. 
     In certain embodiments, the method includes introducing spinal disc implant material into the interior of the annulus and using the anchor member to block extrusion of the implant material through the opening of the annulus. It is also contemplated that the step of actuating can include positioning a proximal surface of the anchor member against a wall of the interior of the disc annulus adjacent the opening therein. The method can include leaving the anchor member in the deployed position as the implant material cures within the interior of the annulus. It is also contemplated that the method can include moving a distal end of a delivery needle into the interior space of the annulus to deliver the implant material, wherein the delivery needle is moved through an interior passage of the blocking device. 
     In accordance with certain embodiments, the anchor member includes a catheter balloon, and the step of actuating the anchor member includes inflating the catheter balloon within the interior of the annulus. The method can include compressing the inflated catheter balloon with implant material. It is also contemplated that the method can include deflating the catheter balloon and withdrawing the blocking device from the opening of the disc annulus. It is also contemplated that the anchor member can include a mesh portion biased radially outward toward the deployed position, wherein the step of actuating the anchor member includes advancing the mesh portion beyond a delivery catheter holding the mesh portion in the undeployed position. The method can include returning the mesh portion to the undeployed position for withdrawal from the annulus by urging the mesh portion into the delivery catheter. A step can also be included for monitoring pressure in the interior of the disc annulus using a pressure sensor operatively connected to the blocking device. 
     The invention also provides an implant delivery device with a blocking component having opposed distal and proximal ends. The proximal end of the blocking component includes a seal member configured and adapted for movement between an undeployed position in which the seal member can pass into and out of an opening in a surgical treatment site, and a deployed position in which the seal member seals the opening in the surgical treatment site to reduce or prevent extrusion of implant material from the opening in the surgical treatment site. An implant delivery needle is located radially within the blocking component and has opposed proximal and distal ends. The needle is configured to deliver implant material from the distal end thereof to an area inside the opening in the surgical treatment site. The seal member can be configured to seal against an opening in a surgical site for kyphoplasty, vertebroplasty, open or percutaneous nucleotomy or discectomy, or any other suitable procedure. 
     These and other features of the systems and methods of the subject invention will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the devices and methods of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein: 
         FIG. 1  is a schematic cross-sectional side elevation view of an exemplary embodiment of a spinal implant delivery device constructed in accordance with the present invention, showing the device being introduced through a cannula to the interior space of a vertebral disc annulus; 
         FIG. 2  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing the anchor member of the device expanded out of the delivery catheter; 
         FIG. 3  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing the implant delivery needle extended into the interior space of the annulus; 
         FIG. 4  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing the anchor member of the device anchored in the interior space of the annulus while implant material is injected through the needle; 
         FIG. 5  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing the interior space of the annulus filled with implant material with the anchor member blocking extrusion of the implant material from the opening of the annulus; 
         FIG. 6  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing the catheter withdrawn from the opening of the annulus with the anchor member holding the device in place; 
         FIG. 7  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing removal of the anchor member from the annulus after the implant material is cured; 
         FIG. 8  is a schematic cross-sectional side elevation view of the device of  FIG. 1 , showing the device withdrawn from the disc annulus with the opening of the disc annulus reapproximated; 
         FIG. 9  is a side elevation view of another exemplary embodiment of a spinal implant delivery device constructed in accordance with the present invention, showing the distal end of the device and the anchor member; 
         FIG. 10  is a cross-sectional side elevation view of a portion of the device of  FIG. 9 , showing the device being introduced through a catheter into an interior space of a disc annulus; 
         FIG. 11  is a cross-sectional side elevation view of a portion of the device of  FIG. 9 , showing the device extended into the interior of the annulus with a portion of the anchor member exposed beyond the end of the catheter; 
         FIG. 12  is a cross-sectional side elevation view of a portion of the device of  FIG. 9 , showing the anchor member expanded to block implant material from extruding out of the annulus opening and to anchor the device in place; 
         FIG. 13  is a cross-sectional side elevation view of a portion of another exemplary embodiment of a spinal implant delivery device constructed in accordance with the present invention, showing the device being introduced through a catheter into an interior space of a disc annulus; 
         FIG. 14  is a cross-sectional side elevation view of a portion of the device of  FIG. 13 , showing the device extended into the interior of the annulus with a portion of the anchor member exposed beyond the end of the catheter; 
         FIG. 15  is a cross-sectional side elevation view of a portion of the device of  FIG. 13 , showing the anchor member expanded to block implant material from extruding out of the annulus opening and to anchor the device in place; 
         FIG. 16  is a side elevation view of the device of  FIG. 13 , showing the anchor member in an unexpanded state; 
         FIG. 17  is a side elevation view of the device of  FIG. 13 , showing the anchor member in an expanded state; 
         FIG. 18  is a side elevation view of the device of  FIG. 13 , showing the anchor member in an expanded state with the distal end concave as though depressed by implant material when inside a disc annulus; and 
         FIGS. 19-21  are perspective views of the device of  FIG. 13 , showing the anchor member in the states of  FIGS. 16-18 , respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject invention. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of the spinal implant delivery device in accordance with the invention is shown in  FIG. 1  and is designated generally by reference character  100 . Other embodiments of spinal implant delivery devices in accordance with the invention, or aspects thereof, are provided in  FIGS. 2-21 , as will be described. The systems and methods of the invention can be used to anchor spinal implant delivery instruments and to block spinal implant material from extruding into undesirable locations. 
     Referring now to  FIG. 1 , a cannula  102  is introduced through the annulus  104  of a spinal disc by conventional percutaneous methods, such as by first placing a percutaneous introducer wire through annulus  104  and creating an opening for cannula  102  by using an obturator introduced over the introducer wire. The nucleus of the disc, or a portion thereof, can be removed by conventional techniques by instruments such as surgical razor blades introduced to the interior of annulus  104  via cannula  102 . Examples of preliminary steps for reaching the state shown in  FIG. 1  are described in general in U.S. Patent Application Publication No. 2009/0024107, to Wilson et al., which is incorporated by reference herein in its entirety. 
       FIG. 1  shows annulus  104  with cannula  102  already introduced, and with the nucleus already removed, as indicated by the texture in  FIG. 1 . Delivery catheter  106  is advanced through cannula  102  into the interior of annulus  104 . Catheter  106  contains an implant delivery needle  108  and a blocking component  110 . The distal end of blocking component  110  includes a mesh portion  112  that is biased outward against the inner surface of catheter  106 . 
     Referring now to  FIG. 2 , needle  108  and blocking component  110  are shown in a position advanced beyond the end of catheter  106 . Mesh portion  112  of blocking component  110  is shown beginning to open, and in this position it is biased against the inner surface of cannula  102 . It is also possible to advance needle  108  and blocking component  110  out of catheter  106  with catheter  106  advanced beyond the end of cannula  102 . 
     As shown in  FIG. 3 , needle  108  can be advanced independent of blocking component  110 . From the position shown in  FIG. 3 , if blocking component  110  is advanced beyond cannula  102 , the biasing force of mesh portion  112  allows full opening of blocking component  110  as shown in  FIG. 4 . Mesh portion  112  is made of a mesh material and in its expanded state within annulus  104 , it blocks the opening of annulus  104  during injection of disk implant material  114 . If the mesh size is too great to prevent a given implant material passing therethrough, then the mesh can advantageously be lined with a thin, stretchable liner made of c-flex polymer, or any other suitable material. 
     It is important to block implant material  114  from extruding beyond the opening created in annulus  104  during the procedure as such extrusions can have detrimental effects on the surrounding nerves.  FIG. 5  shows the nucleus area of annulus  104  filled with implant material  114 , and because the expanded mesh portion  112  of blocking component HQ covers the opening in annulus  104 , implant material  114  is confined in the desired location. As shown in  FIGS. 5-6 , a proximal surface of anchor member  112  is positioned against a wall of the interior of annulus  104  adjacent the opening therein, and since anchor member  112  is larger than the opening in annulus  104 , anchor member  112  retains blocking component  110  at the opening of annulus  104 . 
     With reference now to  FIG. 6 , cannula  102  and catheter  106  can be withdrawn leaving needle  108  and blocking component  110  in place, and allowing annulus  104  to close in around blocking component  110 . Blocking component  110  can be kept in place as implant material  114  cures. This is beneficial because many typical implant materials expand as they cure and without blocking the opening in annulus  104 , implant material  114  would tend to extrude from annulus  104  as discussed above. 
       FIG. 7  shows implant material  114  in a cured state, as indicated by hatching. With implant material  114  set or cured, catheter  106  can be reintroduced over blocking component  110  for removal of blocking component  110  from annulus  104 . Optionally, catheter  106  can be left in place while implant material  114  cures rather than being removed and then later replaced. As blocking component  110  is withdrawn into catheter  106 , the inner wall of catheter  106  causes mesh portion  112  of blocking component  110  to contract as it is removed from the opening in annulus  104 . 
     Referring now to  FIG. 8 , with blocking component  110  fully retracted within catheter  106 , catheter  106 , blocking component  110 , and needle  108  can be removed from annulus  104 . Conventional methods can be used as needed to reapproximate the opening in annulus  104 , as indicated by reference character  116 . 
     Blocking component  110  not only blocks implant material  114  from protruding beyond the opening in annulus  104 , it also maintains or anchors its position as well as that of needle  108  within annulus  104  during the injection and curing of implant material  114 . Typical previously known implant devices require a surgeon to maintain the position manually using at least one hand, which presents a significant challenge since it takes two hands to attach the syringe of implant material to the applicator. Blocking component  110  frees up at least one hand for the surgeon for as much time as needed without the concern of needle  108  or blocking component  110  losing position. In short, by anchoring device  100  in place, blocking component  110  allows for greater ease of application of implant material. 
     Device  100  can be used to deliver implant material through typical posterior approaches, anterior approaches, or by any other suitable approach. Pressure monitoring instruments can be included on needle  108  and/or blocking component  110  to allow monitoring of pressure within annulus  104  during disc repair. 
     While device  100  has been described above in the exemplary context of delivering spinal disc implants, there are other applications to which such devices are well suited. Another exemplary application of such devices is in the delivery of bone-forming substances such as bone morphogenic protein (“BMP”) used to stimulate bone growth. Such materials can be used, for example, to help seal the opening in annulus  104  after the procedure described above. Blocking component  110  can be positioned to prevent leakage of the protein materials onto adjacent boney structures. Leakage of the protein materials could lead to unwanted bone growth, which could result in interference with nerves if used in the spinal region, for example. 
     It is also possible that mesh portion  112  of blocking component  110  can be configured to be detached from blocking component  110 . This would allow blocking component  110  to be left in place within annulus  104  after implant material  114  is injected. Another aspect of the invention is that the implant material  114  can be delivered in a fenestrated collagen bag, which would keep implant material  114  from leaking or protruding beyond annulus  104 , and which would also allow for implant material  114  to adhere to annulus  104 . 
     With reference now to  FIG. 9 , another embodiment of a spinal implant delivery device  200  is shown. Device  200  includes a catheter  206  that is surrounded at least near its distal end with a blocking component  210  that is flexible. In  FIG. 9 , a portion of blocking component  210  is shown cut away to reveal catheter  206 . A ferrule  214  clamps the end of blocking component  210  to catheter  206 . 
     Referring now to  FIG. 10 , device  200  can be introduced to the interior of an annulus  104  by way of a cannula  102  in much the same manner as device  100  described above.  FIG. 10  shows device  200  already introduced at the interior of annulus  104 , which already has the nucleus removed. The center diameter of catheter  206  is sized to admit other instruments therethrough to access the disc interior for removing the nucleus and injecting the implant, much as described above with respect to device  100 . A needle such as needle  108 , or any other suitable delivery device, can be introduced to the interior of annulus  104  through the central passage of catheter  206 , much as described above with respect to device  100 . 
     Prior to injecting an implant into the interior of annulus  104 , device  200  can be used to seal the opening of annulus  104 .  FIG. 11  shows device  200  extended beyond the end of cannula  102  so that ferrule  214  and a portion of blocking component  210  are exposed to the interior space of annulus  104 . In this position, the distal end portion of blocking device  210  can be inflated to serve as an anchor member, as indicated in  FIG. 12 , by using an inflation fluid such as air or any other suitable gas or liquid. The inflated anchor member portion of blocking component  210  forms a catheter balloon  212  within the interior space of annulus  104 . Catheter balloon  212  serves to anchor device  200  in position during the implant procedure so that device  200  cannot accidentally be withdrawn from annulus  104 . This also seals the opening of annulus  104  from implant material leaking therethrough, much as described above with respect to device  100 . 
     As shown in  FIG. 12 , a proximal surface of catheter balloon  212  is positioned against a wall of the interior of annulus  104  adjacent the opening therein, and since catheter balloon  212  is larger than the opening in annulus  104 , catheter balloon  212  retains blocking component  210  at the opening of annulus  104 . When it is desirable to remove device  200 , catheter balloon  212  can be deflated and device  200  can be withdrawn from annulus  104 . 
     With reference now to  FIGS. 13-21 , another embodiment of a device  300  in accordance with the invention is shown. Device  300  includes a flexible blocking component  310  much like blocking component  210  described above, except for the attachment to the respective catheter. Instead of being connected by a ferrule, blocking component  310  is directly attached by any suitable means to catheter  306  with blocking component  310  folded back over its own distal end, as shown in  FIG. 13 . 
     With continued reference to  FIG. 13 , device  300  is shown being introduced through an opening in annulus  104  by way of cannula  102 . Device  300  can be advanced beyond the end of cannula  102 , as indicated in  FIG. 14 , to expose a distal portion of blocking component  310 . The exposed portion of blocking component  310  can be inflated into a catheter balloon  312 , as shown in  FIG. 15 . With catheter balloon  312  anchoring device  300  in place and sealing the opening in annulus  104 , catheter  306  can be used to introduce instruments to inject implant material into the interior of annulus  104 , much as described above. 
       FIG. 16  shows device  300  without a cannula and in the deflated state. In  FIG. 17 , the shape of catheter balloon  312  is shown as it can appear inflated in a disc annulus prior to injection of implant material. Once the implant material has been injected, it will press against catheter balloon  312 , resulting in a catheter balloon shape like that shown in  FIG. 18 , for example.  FIGS. 19-21  show perspective views of the same states of device  300  as shown in  FIGS. 16-18 , respectively. 
     The devices and methods described above have been provided in the exemplary context of open discectomy procedures where the discectomy opening is sealed to prevent re-herniations and to resist further disc degeneration. Those skilled in the art will readily appreciate that the methods and devices described above can readily be used for nucleotomy or discectomy, open or percutaneous. 
     Those skilled in the art will also readily appreciate that the methods and devices described above can also be applied or adapted to any other suitable procedure without departing from the spirit and scope of the invention. For example, vertebroplasty involves a placement of a large needle through a percutaneous or open approach into a vertebral bone that is fractured. Cement is injected to stabilize the bone and reduce pain. Cement leakage is a problem with this approach. A similar approach is Kyphoplasty, which involves the application of a needle with a balloon which is filled with water and expanded to create a void in a broken bone. This allows for correction after a compression fracture has occurred. Kyphoplasty allows for placement of a viscous cement which has a tenancy to migrate because less pressure is needed with the void and more viscous nature of the cement. In these additional exemplary procedures, the devices and methods described herein can readily be applied to anchor catheters and/or to seal or block surgical openings to prevent unwanted migration of implant material. Moreover, those skilled in the art will readily appreciate that the applications of the devices and methods described herein are not limited to spine related procedures, but can be readily adapted to any suitable procedures without departing from the spirit and scope of the invention. 
     The methods and systems of the present invention, as described above and shown in the drawings, provide methods and devices for delivery of spinal disc implants with superior device anchoring and blocking against extrusion of implant material. While the apparatus and methods of the subject invention have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject invention.