Abstract:
Disclosed are devices and methods for accessing and channeling through biological tissue. One embodiment is a bone access tool including a handle assembly and speculum assembly coupled to the handle assembly. The handle assembly has first and second portions that are movable relative to one another. The speculum assembly has first and second speculum members movably positioned relative to one another. The speculum members define an internal shaft arranged about a central axis and a tapered shape when positioned adjacent one another. The tapered shape gradually reduces in size from a proximal rim to a distal edge of the speculum assembly. The speculum assembly also has at least one rib extending outwardly from each of the first and second speculum members, the rib having an upper surface and an inclined lower surface. Actuation of the handle assembly causes the first speculum member and second speculum member to spread apart from one another about the central axis so as to retract anatomical tissue and widen a size of the internal shaft for deploying a tool into the internal shaft between the speculum members.

Description:
REFERENCE TO PRIORITY DOCUMENT 
     This application claims priority of U.S. Provisional Patent Application Ser. No. 60/847,481 filed Sep. 26, 2006. Priority of the aforementioned filing date is hereby claimed and the disclosure of the Provisional Patent Application is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The present disclosure relates to a system for accessing and channeling tissue, such as bone tissue. 
     It is often necessary to access regions of anatomical tissue such as for insertion of a tool for treating or sampling the tissue. For example, a tool is sometimes used to obtain a core sample of biological material such as to diagnose defects or ailments. To obtain a sample, an instrument me be used to remove a portion or a “core sample” from surrounding biological material. In order for the tool to provide a proper approach to the relevant tissue, there is a need for systems and methods that facilitate in gaining access to tissue. 
     SUMMARY 
     There is a need for improved devices and methods for accessing and channeling through biological tissue. 
     In one embodiment, disclosed is a bone access tool including a handle assembly having a first portion and a second portion that are movable relative to one another; a speculum assembly coupled to the handle assembly, the speculum assembly having a first speculum member; a second speculum member movably positioned relative to the first speculum member, wherein the first and second speculum members define an internal shaft therebetween arranged about a central axis, and the first and second speculum members define a tapered shape when positioned adjacent one another, the tapered shape gradually reduces in size from a proximal rim to a distal edge of the speculum assembly; and at least one rib extending outwardly from each of the first and second speculum members, the rib having an upper surface and an inclined lower surface. Actuation of the handle assembly causes the first speculum member and second speculum member to spread apart from one another about the central axis so as to retract anatomical tissue and widen a size of the internal shaft for deploying a tool into the internal shaft between the speculum members. 
     In an embodiment, disclosed is a method of accessing bone, including providing an access tool having a handle assembly coupled to a speculum assembly formed of two speculum members that collectively form a substantially conical shape with a pointed distal edge; navigating the access tool through anatomical tissue so that the pointed distal edge of the speculum assembly is located at a desired anatomical location; actuating the handle to cause the speculum members to separate from one another to retract anatomical tissue and to form a passageway between the speculum members; and positioning an elongated tool in the passageway and in contact with the anatomical location. 
     Other features and advantages will be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosed devices and methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a tissue access and channel formation system. 
         FIG. 2  shows an enlarged view of a speculum assembly of the system with a locking member mounted onto the speculum assembly. 
         FIG. 3  shows a side view of the system in cross-section. 
         FIG. 4  shows a side view of the speculum assembly along line G-G of  FIG. 3 . 
         FIG. 5A  shows a guide wire or guide pin to be inserted into a region of the iliac crest of the pelvis. 
         FIG. 5B  shows the system being guided along the inserted guide pin toward the iliac crest. 
         FIG. 5C  shows the system with the speculum assembly in a possible desired orientation relative to the iliac crest. 
         FIG. 5D  shows a locking member removed from the speculum assembly. 
         FIG. 5E  shows the system with the speculum members displaced from one another to displace and expand surrounding tissue. 
         FIGS. 5F and 5G  show the system with a coring tool positioned at least partially within the passageway between the speculum members. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a perspective view of a tissue access and channel formation system  100 . The system  100  includes a handle assembly  105  and a conical speculum assembly  110  attached to the handle assembly  105 . The handle assembly  105  includes a pair of arms  115  that are pivotably attached to one another about a pivot axis  120 . The arms  115  pivot about a circular pivot member  121  such as when a user actuates the handle assembly  105 . The pivot member  121  can be ratcheted such that movement of the arms  115  relative to one another is controlled by a ratchet mechanism. The arms  115  are shaped and contoured such that the arms extend away from one another at the pivot member  121  and are positioned adjacent one another along a region adjacent the speculum assembly  110 . 
     The speculum assembly  110  is pivotably attached to the handle assembly  105  via a pair of speculum couplers  130 . The speculum assembly  110  includes a pair of semi-conical speculum members  135  that collectively form a conical shape when positioned adjacent one another, as shown in  FIG. 1 . The conical speculum assembly  110  is symmetric about a central axis  410 . In the illustrated embodiment, the speculum assembly  110  is widest at a proximal rim  140  and gradually tapers in diameter toward a distal edge  145  that is pointed. The conical shape facilitates soft tissue penetration and dilation of a surgical access envelope during use of the device, as described below. It should be appreciated that the shape of the speculum assembly  110  can vary from the conical shape and can have other shapes that facilitate soft tissue penetration and dilation of a surgical access envelope. For example, the speculum assembly  110  can have a shape that generally tapers moving in the distal direction with the taper being linear or curvilinear. 
     A speculum cap  150  is removably positioned on the speculum assembly  110  at the proximal rim  140 . The speculum cap  150  forms a flat or generally flat upper surface. The upper surface of the speculum cap  150  provides a location where a striking tool, such as hammer, mallet, or the like, can be used to strike the speculum assembly  110  and provide a downward or distal force to the assembly. This can be desirable when driving the distal edge of the speculum assembly  110  into tissue. The speculum cap  150  can be coupled to the speculum assembly  110  in various manners. For example, the speculum cap  150  can fit within a seat in the upper rim  140  of the speculum assembly  110  or it can hinged or can have locked detent engagement feature with the speculum assembly  110 . The speculum cap  150  can be removed from the speculum assembly  110  to expose an internal speculum shaft  320  ( FIG. 3 ) positioned inside the speculum assembly  110  between the speculum members  135 , as described in detail below. 
     The speculum cap  150  can include an opening or aperture that communicates with the internal speculum shaft  320 . The opening provides a passageway through which a guide pin or guide wire can be inserted. In this regard, the opening desirably has a shape or contour that facilitates insertion of the guide wire into the opening. For example, the opening can be at least partially conical or can have a countersunk feature that facilitates “blind” introduction of the guide wire into the opening. 
       FIG. 2  shows an enlarged view of the speculum assembly  110  with a locking member  205  mounted onto the speculum assembly  110 . The locking member  205  is a clamp-like member that maintains the speculum members  135  in a fixed spatial relationship. For example, the locking member  205  can hold the two arms  115  together to prevent them from spreading apart and thereby prevent spreading of the speculum members  135 . In this regard, the locking member  205  includes a pair of flanges that are positioned on opposite sides of the arms  115  to oppose outward motion of the arms  115 . Thus, when the locking member  205  is mounted on the system, the arms  115  and the attached speculum members  135  are prevented from separating from one another. The locking member  205  is removably mounted on the speculum assembly  110 . A pair of locking member pins  215  removably mate with the locking member  205  and the speculum coupler  130 . The locking member pins  215  can be slidably uncoupled from the speculum coupler  130  to release the locking member  205  from the speculum assembly  110 . 
     With reference still to  FIG. 2 , a guide slot  210  extends through the locking member  205 . The slot  210  communicates with the internal speculum shaft  320  ( FIG. 4 ) located between the speculum members  135 . The slot  210  is aligned or substantially aligned with the central axis  410  of the speculum assembly  110 . A guide pin or guide wire can be positioned through the slot  210  and the internal speculum shaft  320  to assist in navigating through tissue during use of the system, as described more fully below. 
       FIG. 3  shows a side view of the system in cross-section. The opposite side view is a mirror image of the side view shown in  FIG. 3 . Each arm  115  extends along a generally longitudinal axis that intersects the central axis  410 . The end regions of the arms  115  curve downwardly toward the speculum assembly  110 . Each arm  115  is pivotably attached to a respective speculum coupler  130  via a pivot pin  305 . Each pivot pin  305  defines a pivot axis about which the arm  115  can pivot relative to the speculum assembly. Thus, the handle assembly  105  is hinged relative to the speculum assembly  110 . As mentioned, the arms  115  are pivotably attached to one another via the circular pivot member  121 , which can be secured to the arms  115  via a pivot screw that defines a pivot axis about which the arms  115  pivot relative to one another. 
       FIG. 3  shows the internal speculum shaft  320  that is positioned inside the speculum assembly  110 . The speculum shaft  320  has a conical shape with a gradually decreasing diameter that is largest at the proximal rim  140  of the speculum assembly  110 . The speculum shaft  320  gradually tapers in diameter moving toward the distal edge  145  of the speculum assembly  110 . A distal opening  325  is at the distal edge of the speculum assembly  110  such that the speculum shaft  320  is open at the distal edge  145 . The opening  325  aligns or generally aligns along a common axis  410  with the internal speculum shaft  320 , the opening in the speculum cap  150 , and the guide slot  210  ( FIG. 2 ) of the locking member  205 . This permits a guide wire or guide pin to be inserted through the entire speculum assembly  110  and locking member  205  to assist in navigation of the system through tissue during use. 
       FIG. 4  shows a side view of the speculum assembly  110  along line G-G of  FIG. 3 . As discussed, the speculum assembly  110  includes a pair of speculum members  135  that are semi-conical in shape. The speculum members  135  are referred to herein individually as speculum member  135   a  and speculum member  135   b . The speculum members  135  collectively form a conically-shaped speculum when positioned adjacent one another as in  FIG. 4 . The speculum members  135  have walls that meet along a central plane that intersects with the central axis  410  of the conical speculum assembly  110 . The central plane is perpendicular to a plane defined by  FIG. 4 . The speculum members  135  can mate with one another along the adjacent walls such as in an interdigitating manner in order to stabilize the speculum members  135  relative to one another during use of the system  100 . 
     With reference still to  FIG. 4 , one or more protruding flanges or ribs  405  are interspersed along the speculum members from the proximal rim  140  to the distal edge  145 . The illustrated embodiment includes three annular ribs  405  although it should be appreciated that additional ribs  405  or less ribs  405  can be used. The ribs  405  extend radially outward relative to the central axis  410  of the speculum assembly  110 . Each rib  405  has a bottom surface  415  and an upper surface  420 . In the illustrated embodiment, the bottom surface  415  of each rib  405  is upwardly sloped. The upper surface  420  of each rib  405  is horizontal. The upwardly sloped bottom surfaces  415  assist in displacement of tissue upon insertion of the system  100  into tissue and also assist in rotation of the speculum. It should be appreciated that the ribs  405  can have other shapes. 
       FIGS. 5A-5G  are diagrams of an exemplary tissue access and channel formation method that uses the system shown in  FIG. 1 . In an exemplary embodiment, the device and method are used within or in the region of a person&#39;s vertebral bones. For example, the device and method can be employed to gain access to a mammalian patient&#39;s pelvis P, such as in the region of the iliac crest. With reference to  FIG. 5A , a guide wire or guide pin  505  is inserted into a region of the iliac crest. One or more guidance systems can be used to navigate the guide pin  505  to a desired location of the iliac crest. For clarity of illustration,  FIGS. 5A-5G  schematically represent the pelvis P and do not include anatomical structures or tissue that are present around the pelvis P. 
     The tissue access system  100  is then placed over the guide pin  505  and navigated to a desired location of the iliac crest. In this regard, an incision may be made in surrounding tissue and the conical speculum assembly  110  inserted through the incision. The handle assembly  105  can remain outside of the patient&#39;s skin. As discussed, the locking member  205  has a guide slot  210  that communicates with the internal speculum shaft  320 . The tissue access system  100  is guided to the desired iliac crest location by sliding the guide slot  210  and the internal speculum shaft  320  along the guide pin  505 .  FIG. 5B  shows the system  100  being guided along the guide pin  505  toward the iliac crest. 
     The system  100  can advantageously be rotated in various manners as the system navigates through the tissue. For example, the handle assembly  105  and speculum assembly  110  can be rotated about the guide pin  505 . The handle assembly  105  can also rotate relative to the speculum assembly  110  about the pivot pin  305  ( FIG. 3 ). In this manner, the handle assembly  105  can be maneuvered to a desired orientation, such as to enhance the distraction, cut the fascia and tissue adjacent to the crest and correctly orient the speculum assembly  110 .  FIG. 5C  shows the system  100  with the speculum assembly in a possible desired orientation relative to the iliac crest. The system  100  is positioned such that the distal edge of the speculum assembly  110  contacts the iliac crest. As mentioned, a hammer or mallet can be used to apply a force to the speculum assembly  110  for driving the speculum assembly  110  into tissue. 
     After the system  100  has been properly orientated, the physician may remove the locking member  205  from the speculum assembly  110 .  FIG. 5D  shows the locking member  205  removed from the speculum assembly  110 . As mentioned, the locking member pins  215  can be removed to release the locking member  205  from the system  100 . With the locking member  205  removed, the speculum members  135  are free to be separated from one another. This is accomplished by the physician squeezing the arms  115  of the handle assembly  110  toward one another. This causes the distal regions of the arms  115  to pivot away from one another, thereby displacing the speculum members  135  relative to one another.  FIG. 5E  shows the system  100  with the speculum members  135  displaced from one another such that the speculum members  135  displace and expand surrounding tissue. During separation of the speculum members  135 , the ribs  405  stabilize the speculum assembly  110  against the surrounding tissue. A passageway is thereby formed between the speculum members  135  wherein the passageway can be used to visualize the anatomy and/or deliver one or more tools to the iliac crest. In an embodiment, one or more anchor pins  515  can be inserted into the speculum members  135  to immobilize them in the displaced positions. 
       FIGS. 5F and 5G  show the system with a tool  520  positioned at least partially within the passageway between the speculum members  135 . The tool  520  can be any of a variety of tools for treatment or diagnosis of the tissue accessed by the system  100 . In an embodiment, the tool  520  is a tool that is adapted to core into the bone and obtain a sample of the bone. After the tool  520  is used for its intended purpose, the tool  520  can be removed from the passageway between the speculum members  135 . The anchor pins  515  can then be removed and the separation between the speculum members  135  can be reduced by operating the handle assembly  105 . The system  100  can then be removed by navigating out of the tissue. The generally horizontal upper surfaces  420  of the ribbing is generally perpendicular to the direction of withdrawal to reduce the potential for ejection with soft tissue tensioning. The locking member  205  can be re-attached prior to removal of the system  100 . In addition, the handle assembly  105  can be rotated during removal to ease removal. 
     Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the snowboard binding should not be limited to the description of the embodiments contained herein.