Abstract:
A percutaneous and minimally invasive instrument system for implanting an interspinous process spacer into a patient is disclosed. The insertion instrument system includes an inserter and a driver. The inserter is configured to releasably clamp to an interspinous process spacer for its delivery, implantation and deployment. The driver is configured for removable insertion into a proximal end of a passageway of the inserter. The driver has a distal spacer engaging portion configured to engage that part of the spacer requiring activation for the deployment of the spacer from at least one undeployed configuration to at least one deployed configuration and vice versa. As the spacer goes from the undeployed to the deployed configuration and vice versa, the system advantageously provides a degree of deployment information to the user via at least one deployment indicator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of and is a continuation-in-part of U.S. Provisional Patent Application Ser. No. 61/069,083 entitled “Spacer instrumentation system with deployment indicator” filed on Mar. 12, 2008 which is incorporated herein by reference in its entirety. This application also claims priority to and is a continuation-in-part of U.S. patent application Ser. No. 12/354,517 entitled “Interspinous spacer” filed on Jan. 15, 2009 which is a non-provisional of U.S. Provisional Patent Application No. 61/011,199 entitled “Interspinous spacer” filed on Jan. 15, 2008 both of which are incorporated by reference herein in their entireties. This application also claims priority to and is a continuation-in-part of U.S. patent application Ser. No. 12/338,793 entitled “Spacer insertion instrument” filed on Dec. 18, 2008 which is a non-provisional of U.S. Provisional Patent Application Ser. No. 61/008,418 entitled “Spacer insertion instrument” filed on Dec. 19, 2007 both of which are incorporated herein by reference in their entireties. This application also claims priority to and is a continuation-in-part of U.S. patent application Ser. No. 12/205,511 entitled “Interspinous spacer” filed on Sep. 5, 2008 which is a non-provisional of U.S. Provisional Patent Application Ser. No. 60/967,805 entitled “Interspinous spacer” filed on Sep. 7, 2007 and a continuation-in-part of U.S. patent application Ser. No. 12/220,427 entitled “Interspinous spacer” filed on Jul. 24, 2008 which is a non-provisional of U.S. Provisional Patent Application Ser. No. 60/961,741 entitled “Insterspinous spacer” filed on Jul. 24, 2007 and is a continuation-in-part of U.S. patent application Ser. No. 12/217,662 entitled “Interspinous spacer” filed on Jul. 8, 2008 which is a non-provisional of U.S. Provisional Patent Application No. 60/958,876 entitled “Interspinous spacer” filed on Jul. 9, 2007 and a continuation-in-part of U.S. patent application Ser. No. 12/148,104 entitled “Interspinous spacer” filed on Apr. 16, 2008 which is a non-provisional of U.S. Provisional Patent Application Ser. No. 60/923,971 entitled “Interspinous spacer” filed on Apr. 17, 2007 and U.S. Provisional Patent Application Ser. No. 60/923,841 entitled “Spacer insertion instrument” filed on Apr. 16, 2007, all of which are hereby incorporated by reference in their entireties. This application is also a continuation-in-part of U.S. patent application Ser. No. 11/593,995 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Nov. 7, 2006 and a continuation-in-part of U.S. patent application Ser. No. 11/582,874 entitled “Minimally invasive tooling for delivery of interspinous spacer” filed on Oct. 18, 2006 and a continuation-in-part of U.S. patent application Ser. No. 11/314,712 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Dec. 20, 2005 and a continuation-in-part of U.S. patent application Ser. No. 11/190,496 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Jul. 26, 2005 and a continuation-in-part of U.S. patent application Ser. No. 11/079,006 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Mar. 10, 2005 and a continuation-in-part of U.S. patent application Ser. No. 11/052,002 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Feb. 4, 2005 and a continuation-in-part of U.S. patent application Ser. No. 11/006,502 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Dec. 6, 2004 and is a continuation-in-part of U.S. patent application Ser. No. 10/970,843 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Oct. 20, 2004 and a continuation-in-part of U.S. patent application Ser. No. 11/006,521 entitled “Systems and methods for stabilizing the motion or adjusting the position of the spine” filed on Dec. 6, 2004, and is a continuation-in-part of U.S. patent application Ser. No. 11/305,820 entitled “Systems and methods for posterior dynamic stabilization of the spine” filed on Dec. 15, 2005, all of which are hereby incorporated by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    With spinal stenosis, the spinal canal narrows and pinches the spinal cord and nerves, causing pain in the back and legs. Typically, with age, a person&#39;s ligaments may thicken, intervertebral discs may deteriorate and facet joints may break down—all contributing to the condition of the spine characterized by a narrowing of the spinal canal. Injury, heredity, arthritis, changes in blood flow and other causes may also contribute to spinal stenosis. 
         [0003]    Doctors have been at the forefront with various treatments of the spine including medications, surgical techniques and implantable devices that alleviate and substantially reduce debilitating pain associated with the back. In one surgical technique, a spacer is implanted between adjacent spinous processes of a patient&#39;s spine. The implanted spacer opens the spinal canal, neural foramen, maintains the desired distance between vertebral body segments, and as a result, reduces the impingement of nerves and relieves pain. For suitable candidates, an implantable interspinous spacer may provide significant benefits in terms of pain relief. 
         [0004]    Any surgery is an ordeal. However, the type of device and how it is implanted has an impact. For example, one consideration when performing surgery to implant an interspinous spacer is the size of the incision that is required to allow introduction of the device. Small incisions and minimally invasive techniques are generally preferred as they affect less tissue and result in speedier recovery times. As such, there is a need for interspinous spacers and instruments that are used to implant them that work well with surgical techniques that are percutaneous and/or minimally invasive for the patient that can also be used in an open or mini-open procedure. The present invention sets forth such an instrument system. 
       SUMMARY 
       [0005]    According to one aspect of the invention, an instrument system is provided. The system includes an interspinous process spacer, an inserter, a driver and a deployment indicator. The inserter is configured to releasably attach to the spacer at one end for implanting the spacer into a patient&#39;s interspinous process space. The driver that is connected to the inserter is configured to arrange the spacer from at least one undeployed configuration to at least one deployed configuration and the deployment indicator provides at least one information to the user pertaining to the degree of deployment of the attached spacer. 
         [0006]    According to another aspect of the invention, an instrument for inserting a deployable interspinous process spacer into a patient is provided. The instrument includes a first end connectable to an interspinous process spacer and a second end configured to arrange a connected spacer between at least a first configuration and at least a second configuration. The instrument includes a sensor configured to measure the arrangement of a connected spacer and provide a signal regarding the arrangement of a connected spacer to the user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0007]      FIG. 1A  illustrates a side view of a spacer instrument system connected to a spacer in a closed or an undeployed configuration according to the present invention. 
           [0008]      FIG. 1B  illustrates a side view of a spacer instrument system connected to a spacer in an open or deployed configuration according to the present invention. 
           [0009]      FIG. 2  illustrates a perspective partial end view of an inserter and driver of a spacer instrument system according to the present invention. 
           [0010]      FIG. 3A  illustrates a perspective view of a driver according to the present invention. 
           [0011]      FIG. 3B  illustrates a side view of a driver according to the present invention. 
           [0012]      FIG. 3C  illustrates a cross-sectional view taken along line A-A of  FIG. 3B  of the driver according to the present invention. 
           [0013]      FIG. 3D  illustrates a side view of a driver according to the present invention. 
           [0014]      FIG. 4A  illustrates a perspective view of a spacer in an undeployed or closed configuration according to the present invention. 
           [0015]      FIG. 4B  illustrates a perspective view of a spacer in a deployed or open configuration according to the present invention. 
           [0016]      FIG. 4C  illustrates a top view of a spacer in a deployed or open configuration according to the present invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0017]    Referring first to  FIGS. 1A and 1B , there is shown a spacer instrument system  10  with a deployment indicator according to the present invention connected to an interspinous process spacer  12  in a closed or undeployed configuration and in an open or deployed configuration, respectively. The spacer instrument system  10  includes an inserter  14  and a driver  16 . 
         [0018]    Still referencing  FIGS. 1A and 1B  and with additional reference to  FIG. 2 , the inserter  14  will now be described. The inserter  14  is of the type described in co-pending U.S. patent application Ser. No. 12/338,793 entitled “Spacer insertion instrument” filed on Dec. 18, 2008 which claims the benefit of U.S. Provisional patent application Ser. No. 61/008,418 entitled “Spacer insertion instrument” filed on Dec. 19, 2007 both of which are assigned to VertiFlex, Inc. and hereby incorporated by reference in their entireties. The inserter  14  is configured to releasably clamp to a body of an interspinous process implant or spacer  12  to be delivered into or removed from a patient using the system  10 . The inserter  14  includes an inner shaft  18 , an outer shaft  20 , a control  22  and handle assembly  24 . The inner shaft  18  is connected to the handle assembly  24  of the inserter  14  and the outer shaft  20  is passed over the inner shaft  18  and allowed to translate with respect to the inner shaft  18  by means of a control  22  that is threadingly engaged with the outer shaft  20 . With rotation of the control  22  in one direction, the outer shaft  20  translates distally with respect to the stationary inner shaft  18 . With rotation of the control  22  in the opposite direction, the outer shaft  20  translates proximally with respect to the stationary inner shaft  18 . In another variation of the invention, the outer shaft  20  is connected to handle assembly  24  and the inner shaft is threadingly connected to the control  22  such that rotation of the control  22  moves the inner shaft  18  with respect to the outer shaft  20  proximally or distally. Although rotation of the control  22  is used in one variation, other variations are within the scope of the present invention such as, for example, translation of the control  22  or movement of the outer shaft  20  relative to the inner shaft  18 . 
         [0019]    With particular reference to  FIG. 2 , the inner shaft  18  of the inserter  14  is substantially cylindrical in shape having a central bore extending from end to end. 
         [0020]    The distal end of the inner shaft  18  includes a pair of prongs  26  with each prong being substantially oppositely located from each other. The finger-like prongs  26  are flexible and, when in a normal position, splay slightly outwardly from the longitudinal axis. The prongs  26  are configured to connect with the spacer  12 . In particular, the prongs  26  include extensions  28  that extend inwardly toward the longitudinal axis in a hook-like fashion. These extensions  28  are configured to be inserted into prong-receiving portions  30  (see  FIGS. 4A ,  4 B and  4 C) on the spacer  12  and securely clamp thereto. The prongs  26  also include conforming surfaces configured to conform to the spacer  12  in a manner best suited for secure attachment thereto. The proximal end of the inner shaft  18  is configured for insertion into and connection with a conformingly shaped recess in the handle  24 . 
         [0021]    The outer shaft  20  of the inserter  14  will now be described. As seen in  FIG. 2 , the outer shaft  22  is substantially cylindrical in shape having a central bore  32  extending from end to end. The outer shaft  20  is sized such that the inner shaft  18  fits inside the outer shaft  20 . The distal end includes a pair of flattened portions  34  located substantially opposite from each other for a narrower profile and in one variation a ramped profile for insertion or placement between adjacent spinous processes of a patient&#39;s spine. The ramped profile serves to distract the adjacent spinous processes apart slightly as the inserter is being inserted between the adjacent spinous processes for insertion of the connected spacer  12  wherein the flattened portions  34  are separated by an increasingly wider distance towards the proximal end of the instrument. The outer shaft  20  includes a threaded proximal portion (not shown). The threaded proximal portion is configured for threaded connection with the control  22  such that movement of the control  22  moves the outer shaft  20 . 
         [0022]    The control  22  includes a user interface such as a finger portion or grip. In one variation, the user interface is an outer circular or disk-shaped portion for easily effecting rotation of the control  22  with a thumb or index finger. The control  22  is configured to effect relative translation of the inner shaft  18  with respect to the outer shaft  20 . 
         [0023]    The spacer instrument system  10  functions to engage with, insert and deploy an interspinous spacer  12  in an interspinous process space between two adjacent vertebrae. Illustrative examples of interspinous spacers that are compatible with the insertion instrument are described in applicant&#39;s co-pending U.S. patent application Ser. No. 12/148,104 entitled “Interspinous spacer” filed on Apr. 16, 2008 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/923,841 entitled “Spacer insertion instrument” filed on Apr. 16, 2007 and U.S. Provisional Patent Application Ser. No. 60/923,971 entitled “Interspinous spacer” filed on Apr. 17, 2007, U.S. patent application Ser. No. 12/217,662 entitled “Interspinous spacer” filed on Jul. 8, 2008 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/958,876 entitled “Interspinous spacer” filed on Jul. 9, 2007, U.S. patent application Ser. No. 12/220,427 entitled “Interspinous spacer” filed on Jul. 24, 2008 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/961,741 entitled “Interspinous spacer” filed on Jul. 24, 2007, and U.S. patent application Ser. No. 12/205,511 entitled “Interspinous spacer” filed on Sep. 5, 2008 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/967,805 entitled “Interspinous spacer” filed on Sep. 7, 2007, and U.S. patent application Ser. No. 12/354,517 entitled “Interspinous spacer” filed on Jan. 15, 2009 which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/011,199 entitled “Interspinous spacer” filed on Jan. 15, 2008 the disclosure of all of which are incorporated herein by reference in their entireties. An example of an interspinous spacer  12  is shown in  FIGS. 4A ,  4 B and  4 C. In general, each spacer  12  includes a body portion  36  with at least one prong receiving portion  30  for connecting with the instrument  10 , at least one wing  40  rotatably connected to the body  36  and an actuator shaft  38  housed in the body portion  36  and configured to arrange the at least one wing  40  from at least one undeployed configuration (see  FIG. 4A ) to at least one deployed configuration (see  FIGS. 4B and 4C ) and vice versa. The wings  40  are configured to laterally stabilize the body portion  36  relative to thespinous processes, seat and/or space apart the spinous processes of adjacent vertebrae when in the deployed configuration to relieve pain. 
         [0024]    The spacer instrument system  10  utilizes the working channel that is preferably created by the use of one or more tools such as a target needle, K-wire, dilators, mounting bracket, cannula, stabilizing arm, interspinous knife, interspinous reamer, and interspinous gage, all described in applicant&#39;s co-pending U.S. patent application Ser. No. 11/582,874 entitled “Minimally invasive tooling for delivery of interspinous spacer” filed on Oct. 18, 2006, incorporated herein by reference in its entirety. The inserter  14  is typically inserted through a cannula with the distal end positioned at the interspinous process space in a minimally invasive, percutaneous, mini-open or open surgical procedure. In some procedures, a cannula is not employed to deliver the spacer instrument system  10  and spacer  12  to the interspinous space. 
         [0025]    In use, a spacer  12  is placed in juxtaposition to the distal end of the inserter  14  such that the prongs  26  of the inserter  14  are adjacent to the prong receiving portions  30  on the spacer  12 . The control  22  is then activated to clamp the prongs  26  of the inner shaft  18  onto the spacer  12 . In particular, the control  22  is rotated in one direction which advances the outer shaft  20  over the inner shaft  18  to thereby inwardly deflect the outwardly splayed prongs  26  at the distal end of the inner shaft  18 . This inward deflection allows the prongs  26  to engage the spacer body  36  and, in particular, allows the prong extensions  28  to be inserted into the prong receiving portions  30  and with further rotation of the control  22  to lock the inserter  14  securely onto the spacer  12 . Reverse rotation of the control  22  translates the outer shaft  20  proximally to expose the prongs  26  allowing them to splay outwardly to their pre-stressed normal position and thereby release the spacer  12  from the inserter  14 . 
         [0026]    If a cannula is employed in the operative site, the inserter  14  with the attached spacer  12  is sized to fit through a cannula and is passed through the cannula to the interspinous process space. Once in position inside the patient, the driver  16  is inserted into the proximal opening of the central passageway of the inserter  14  and passed until the driver  16  connects with the spacer  12 . 
         [0027]    Turning now to  FIGS. 3A ,  3 B,  3 C and  3 D, the driver  16  will now be described. The driver  16  includes: (1) a handle  42  having a proximal end  44  and a distal end  46 , (2) a inner shaft  48 , (3) outer shaft  50 , (3) a spacer engaging bit  54  connected to the distal end of the outer shaft  50 , and (4) a spring  52 . The outer shaft  50  which is connected to the distal end  46  of the handle  42  includes a lumen in which the inner shaft  48  is disposed. The inner shaft  48  includes a collar  56  (shown in  FIG. 3C ) configured to be located inside the handle  42  and biased against the spring  52  and configured such that the spring  52  forces the inner shaft  48  distally in a direction towards the spacer engaging bit  54 . The proximal end  44  of the handle  42  includes a deployment indicator window  58  through which the inner shaft  48  is viewed.  FIG. 2  illustrates the distal end of the driver  16  inserted into the inserter  14 . 
         [0028]    Depending on the spacer  12  design, the connection of the driver  16  with the spacer  12 , in particular the spacer engaging bit  54 , will be different. In general, however, the driver  16  connects to the spacer  12  such that movement, such as rotation, of the driver  16  effects deployment of a deployable spacer  12 , in particular, the deployment of the at least one wing  40  of the spacer  12 . In particular, and with respect to the spacer embodiment shown in  FIGS. 4A-4C , rotation of the driver  16  that is connected to the spacer  12  effects translation of the actuator shaft  38  of the spacer  12  which in turn is connected to the at least one wing  40  causing it to deploy into an expanded configuration or deployed configuration. 
         [0029]    The driver  16  that is configured to connect with the spacer  12  of  FIGS. 4A-4C  will have a spacer engaging bit  54  that includes two projecting features  60 . The two projecting features  60  engage complementary features  62  on the spacer  12  located inside the spacer body portion  36  as shown in  FIGS. 4A-4C . Once engaged to the spacer  12 , rotation of the driver  16  rotates the spindle  64  which in turn advances the actuator shaft  38  to deploy the wings  70  into the configuration shown in  FIGS. 4B and 4C . Reverse rotation of the driver  16  will turn the spindle  64  in an opposite direction and proximally translate the actuator shaft  38  to undeploy the wings  40 . As can be seen in  FIGS. 4B and 4C , when in the deployed configuration, the actuator shaft  38  is distally translated with rotation of the driver  16  relative to when in the undeployed configuration as shown in  FIG. 4A  wherein the actuator shaft  38  projects proximally from the spacer body  36 . This distance traveled by the actuator shaft  38  provides the information about the degree of deployment of the wings  40  of the spacer  12  that is communicated to the inner shaft  48  of the driver  16 . With the inserter  14  connected to the spacer  12  and the driver  16  inserted into the central passageway of the inserter  14  and connected to the spindle  64  such that the projecting features  60  of the bit  54  engage the features  62  on the spindle  64 , the inner shaft  48  of the driver  16  contacts the proximal end  66  of the actuator shaft  38  and will bias the inner shaft  48  a distance related to the distance with which the actuator shaft  38  projects proximally from the spacer body  36 . Hence, as the driver  16  is rotated to effect translation of the actuator shaft  38  inwardly or outwardly to deploy or undeploy the spacer, the bias force of the spring  52  will keep the distal end of the inner shaft  48  of the driver  16  in contact with the proximal end  66  of the actuator shaft  38  as it translates proximally or distally providing an indication as to the degree of deployment of the spacer  12 . The indication as to the degree of deployment of the spacer  12  is viewed at the proximal end of the system  10 . Because the handle  24  resides outside the patient, the deployment information is readily visible to the surgeon. 
         [0030]    Referring back to  FIG. 1A , there is shown the system  10  in an undeployed configuration. As can be seen, at the proximal end, the inner shaft  48  projects outwardly from the proximal end  44  of the handle  24 . As the driver  16  is rotated to deploy the spacer  12 , the inner shaft  48  moves distally until the inner shaft  48  does not project outwardly from the proximal end  44  of the handle  24  and/or is co-planar with the proximal end  44  of the handle  24  as shown in  FIG. 1B , thereby providing the user with a visual indication of the degree of deployment of the spacer  12  wherein if the inner shaft  48  is not projecting then the spacer  12  is fully deployed and if the inner shaft  48  is projecting from the proximal end  44  of the handle  24  then a state other than full deployment is indicated. The degree of deployment is related to the distance with which the inner shaft  48  is projecting outwardly from the proximal end  44  of the handle  24 . The proximal end of the inner shaft  48  or “button” provides the surgeon not only with visual feedback but also tactile feedback as to the degree of deployment. 
         [0031]    Another deployment indicator is provided alternatively or in conjunction with the projection of the inner shaft  48  from the proximal end  44  just described. This other deployment indicator includes an indicator line  68  (shown in  FIGS. 1B and 3D ) provided on the inner shaft  48  of the driver  16 , which becomes visible through the indicator window  58  as the inner shaft  48  translates with deployment of the spacer  12 . When in the undeployed configuration as shown in  FIG. 1A , the indicator line  68  is proximal of the window  58  and therefore not visible through the indicator window  58 . When the spacer  12  approaches a deployed configuration, the indicator line  68  will enter the indicator window  58  and be visible to the user. An additional alignment line or lines  70  is provided on the proximal end  44  of the handle  24  adjacent to the indicator window  58  as shown in  FIGS. 1B and 3D . When the indicator line  68  on the inner shaft  48  is aligned with the alignment line or lines  70  on the handle  24 , a fully deployed configuration of the spacer  12  is indicated providing a visual information of deployment to the surgeon. 
         [0032]    The above description is one variation of mechanical sensor connected to the instrument for measuring the arrangement of a connected spacer  10 . One skilled in the art will recognize that the instrument can be configured with any suitable sensor that can be effectively employed to measure the arrangement of the spacer and provide a signal to the user regarding the arrangement of the connected spacer. Examples of suitable sensors include, but are not limited to mechanical, position, optical, electromagnetic, motion, and distance sensors. Of course, suitable signals communicating the measured information include audible, visual, tactile signals and the like. The signal may be transmitted to a receiver located on the instrument itself preferable at a location that is resident outside the patient while in use or at a location remote of the instrument. In one variation, the sensor provides a signal only upon full deployment of the spacer. In another variation, the sensor provides continuous information as to the arrangment of the spacer. 
         [0033]    Hence, the present invention advantageously provides information regarding the degree of deployment of the spacer to the surgeon which is particularly advantageous in minimally invasive and percutaneous procedures where the device cannot be viewed without the aid of fluoroscopy because of visual obstruction accompanying very small incisions. As a result of the deployment information provided by the system, this invention advantageously reduces time required to implant the spacer and also advantageously reduces the number of fluoroscopy shots that the clinicians and patients are exposed to during the procedure as the deployment information is readily provided to the surgeon by the spacer instrument system with deployment indicator that is located outside patient incision. 
         [0034]    All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The preceding illustrates the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope.