Abstract:
An instrument channel device for receiving a medical instrument having a distal tip includes an elongate tubular shaft including a proximal shaft portion and a distal shaft portion positionable within a body cavity. The shaft defines a lumen for passage of the distal tip of a flexible medical instrument therethrough, allowing positioning of the medical instrument such that its distal tip is disposed distally of the distal shaft portion. A telescoping reinforcement is positioned on the distal shaft portion. The reinforcement has a collapsed position in which the telescoping reinforcement has a length that is shorter than the length of the telescoping reinforcement in an expanded position. As an instrument is advanced from the distal end of the lumen, the telescoping reinforcement is engaged by a distal portion of the instrument such that advancement of the distal tip to a position beyond a distal end of the telescoping reinforcement moves the telescoping reinforcement to the expanded position. The reinforcement minimizes unintended flexion of the portion of the instrument shaft that extends beyond the distal end of the lumen.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/728,296, filed Nov. 20, 2012, and U.S. Provisional Application No. 61/801,781, filed Mar. 15, 2013, each of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of steerable channel devices for minimally invasive surgical procedures, and more particularly to reinforcements for minimizing unintended deflection of the shafts flexible instruments steered by steerable channel devices during use. 
       BACKGROUND 
       [0003]    Surgery in the abdominal cavity is frequently performed using open laparoscopic procedures, in which multiple small incisions or ports are formed through the skin and underlying muscle and peritoneal tissue to gain access to the peritoneal site using the various instruments and scopes needed to complete the procedure. The peritoneal cavity is typically inflated using insufflation gas to expand the cavity, thus improving visualization and working space. Further developments have led to systems allowing such procedures to be performed using fewer ports, and in some cases only a single port. 
         [0004]    Some instrument access devices or ports suitable for use in single port procedures and other laparoscopic procedures are described in co-pending U.S. application Ser. No. 11/804,063 (US Publication 2007-0299387) filed May 17, 2007 and entitled SYSTEM AND METHOD FOR MULTI-INSTRUMENT SURGICAL ACCESS USING A SINGLE ACCESS PORT, U.S. application Ser. No. 12/209,408 (US Publication 2009-227843) filed Sep. 12, 2008 and entitled MULTI-INSTRUMENT ACCESS DEVICES AND SYSTEMS, and U.S. application Ser. No. 12/511,043 (US Publication 2011-0060183) filed Jul. 28, 2009, entitled MULTI-INSTRUMENT ACCESS DEVICES AND SYSTEMS, and U.S. application Ser. No. 12/846,788 (US Publication US 2011-0184231), entitled DEFLECTABLE INSTRUMENT PORTS, filed Jul. 29, 2010, and U.S. application Ser. No. 13/651,278 (Attorney Docket: TRX-2620), entitled Deflectable Instrument Shafts, filed Oct. 12, 2012, each of which is incorporated herein by reference. The aforementioned patent applications describe access systems incorporating at least one and in some cases multiple steerable instrument channel devices. 
         [0005]    Referring to  FIG. 1  in which the distal portion of a steerable instrument channel device is shown, each such steerable instrument channel device  210  includes a lumen  220  for receiving a flexible medical instrument  230 . The instrument channel device  210  includes a proximal shaft portion  202  and a steerable/deflectable portion  200 . The steerable/deflectable portion  200  is actively steered using an actuator positioned proximally on the device  210  for manipulation by a user. Manipulation of the actuator engages pull elements or other actuation components coupled to the portion  200  to effect steering. Thus the instrument channel device  210  is used to support and steer the flexible medical instrument passed through it. Medical instruments that may be used through such steerable channels include, but are not limited to, flexible-shaft forceps, graspers, dissectors, electrosurgical instruments, retractors, scopes, and tissue securing devices such as suture devices or staplers. 
         [0006]    The medical instrument is one having a flexible shaft  240  and an end effector  250  on the distal end of the flexible shaft. The medical instrument may further include a handle (not shown) on the proximal end of the shaft. The handle may include an actuator used for actuating the end effector, such as by opening/closing jaws, applying a staple or other fastener etc, or features for energizing an electrosurgical element. 
         [0007]    In use, the distal portion of the flexible instrument is passed through the steerable instrument channel such that the end effector  250  exits the distal end of the steerable instrument channel. Deflection or steering of the flexible instrument is carried out by actively steering or deflecting the distal portion of the steerable instrument channel. The flexible instrument is removably received within the lumen of the steerable instrument channel so that it may be interchanged with other medical instruments during the course of the procedure. 
         [0008]    In some instances, a portion of the medical instrument&#39;s flexible shaft  240  may be positioned distal to the distal end of the steerable instrument channel, and thus may undesirably flex within the body. For example, the flexible instrument shaft may flex as the end effector is engaged with tissue, contacts or advances against tissue, or is used for tissue manipulation. Such flexion may occur during times when the instrument channel is actively steered and also when the user is not actively steering the channel. The present application describes a feature that may be used at the distal end of a steerable instrument channel to minimize such unintended flexion of the flexible instrument shaft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view showing the distal end portion of the shaft of a prior art steerable instrument channel device, with a flexible instrument and its end effector extending from the distal end of the shaft; 
           [0010]      FIG. 2A  is a perspective view showing the distal end portion of a first embodiment of a shaft comprising a steerable portion and a telescoping reinforcement, in which the telescoping reinforcement is shown in the collapsed position; 
           [0011]      FIG. 2B  is similar to  FIG. 2A , shows the telescoping reinforcement in the extended position, and further shows an end effector of a flexible instrument extending from the distal end of the shaft; 
           [0012]      FIG. 3  is an exploded perspective view of the telescoping reinforcement of  FIGS. 2A and 2B ; 
           [0013]      FIGS. 4A and 4B  are side elevation views of telescoping members of the telescoping reinforcement of  FIGS. 2A and 2B ; 
           [0014]      FIG. 5  is a perspective view of the steerable portion of the shaft of  FIGS. 2A and 2B ; 
           [0015]      FIGS. 6  is a perspective exploded view of three vertebrae of the steerable portion of  FIG. 5 ; 
           [0016]      FIG. 7  is a perspective top view of the ball vertebrae of  FIG. 6 ; 
           [0017]      FIG. 8  is similar to  FIG. 6 , but shows the vertebrae in a straight configuration; 
           [0018]      FIG. 9A  is a perspective view showing the distal end portion of a second embodiment of a shaft comprising a steerable portion and a telescoping reinforcement, in which the telescoping reinforcement is shown in the collapsed position; 
           [0019]      FIG. 9B  is similar to  FIG. 9A  and shows the telescoping reinforcement in the extended position. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    This application describes reinforcing elements positioned at a distal end of an instrument channel device through which the distal ends of medical instruments are delivered to an operative site within a body cavity. The reinforcing elements are disclosed as positioned at the end of an instrument channel device having a steerable distal portion, although they might instead be used on other types of instrument channel devices. 
         [0021]      FIG. 2A  is a perspective view showing a first embodiment including a shaft  100  comprising a steerable portion  102  coupled to the distal portion of a proximal shaft portion (not shown but see proximal shaft portion  202  of  FIG. 1 ), and a telescoping reinforcement  104  disposed at the distal end of the steerable portion  102 . The steerable portion  102 , proximal shaft, and telescoping reinforcement define a lumen  106  for removably receiving a medical instrument. A port at the proximal end of the shaft  100  provides access for instruments into the lumen  106 . 
         [0022]    The proximal shaft portion may be a flexible, rigid, semi-rigid, or rigidizable tubular shaft. Examples are found in the co-pending patent applications referenced in the Background section above. 
         [0023]    Telescoping reinforcement  104  is formed of a plurality of telescoping members  108   a - 108   e  having a collapsed position as shown in  FIG. 2A  (in which only the outermost, proximalmost, telescoping member  108   a  is visible) and an extended position in which the reinforcement  104  is longitudinally expanded as shown in  FIG. 2B . The members  108   a - 108   e  of the first embodiment are a plurality of longitudinally-arranged tubular members, with each member shaped to nest within the proximally-adjacent member. For example, the members may be cylindrical members, each of which has an outer diameter that is smaller than the inner diameter of its proximally-adjacent neighbor. The members are formed of a rigid material such as stainless steel. Where instruments having electrosurgical tips are to be used through the instrument channel, at least the distal member  108   e  may be formed of a thermally insulative material such as PEEK so as to prevent the telescoping reinforcement  104  from heating during use of the electrosurgical tips. 
         [0024]    Members  108   a - 108   d  include longitudinally extending slots or cutouts  110  in their side walls. Each member may include more than one such slots. For example, in the illustrated embodiment each member includes a pair of longitudinally extending slots  110  spaced 180° from one another. In the drawings the slots  110  in members  108   a  and  108   c  are shown off-set 90° from the slots  110  in members  108   b  and  108   d.  Different (or no) offsets may be used in other embodiments. Each slot has a distal end as shown. 
         [0025]    Detents  112  (best seen in  FIG. 3 ) are formed in the side walls of members  108   b - 108   e.  When the telescoping reinforcement is in the expanded position as shown in  FIG. 2B  (and optionally also in the collapsed position of  FIG. 2A ), each detent  112  of a member  108   b - 108   e  is radially and circumferentially aligned with the slot  110  of that member&#39;s proximally adjacent neighbor  108   a - 108   d.  Detents  112  are biased in a slight radially-outward direction, such that when the telescoping reinforcement is expanded each detent  112  abuts the distal end of its corresponding slot  110 , which forms a stop against further movement of the member having the detent relative to the member having the corresponding slot  110 . 
         [0026]    Prior to insertion of a medical instrument through the lumen  106 , the members  108   a - 108   e  are arranged in the nested configuration shown in  FIG. 2A . Some embodiments are equipped with features that retain the members  108   a - 108   e  in this nested configuration so that the telescoping reinforcement will only move to the expanded position of  FIG. 2B  when actively made to do so. This avoids inadvertent expansion of the telescoping reinforcement that might occur during movement of the steerable instrument channel (e.g. during preparation of the device for use or during insertion into the body cavity). In the  FIG. 2A-4B  embodiments, each of the members  108   a - 108   d  includes a pair of deflecting members  114  formed at the proximal end of each slot  110 . When a telescoping member (e.g. member  108   b ) is moved proximally such that its detent  112  contacts deflecting members  114  of its proximally adjacent neighbor  108   a,  deflecting members  114  flex slightly away from one another, allowing the detent  112  to pass between them and thus capturing the detent  112  between their opposed surfaces. Each pair of deflecting members  114  is thus positioned to engage the corresponding detent  112  of the distally adjacent neighbor  108   b - 108   e.    
         [0027]    In alternate embodiments, magnetic features at the proximal end of the telescoping reinforcement are used to retain the members  108   a - 108   e  in the proximal, nested, configuration by engaging with magnetic material disposed on the distal member  108   e.    
         [0028]    In other alternate embodiments, elastomeric materials including, but not limited to, silicone or extension springs  107  may be terminally attached to distal member  108   e  such that extension of the telescoping members is opposed by a spring force exerted by the elastomeric member. 
         [0029]    Other alternate embodiments may include a retention mechanism that may be released by rotation or other actuation means perpetrated by the distal end of the instrument shaft or end effector. In these embodiments, extension of members  108   a - 108   e  is impeded by a mechanical stop that must be engaged by the instrument end effector to be released. 
         [0030]    The steerable portion  102  of the instrument shaft  100  may take one of many forms suitable for use in constructing a steerable instrument shaft, including flexible tubing, vertebrae segments, slotted tubing (e.g. laser cut tubing) etc.  FIGS. 5 through 8  show one type of vertebrae arrangement may be used to form the steerable portion. This arrangement uses a strand of ball segments  120  alternating with socket segments  122 . Each ball segment  120  has at least a partially spherical exterior surface, and each socket segment  122  has a beveled or partially spherical interior surface for receiving a portion of the ball segment&#39;s outer surface. This arrangement forms a generally smooth and continuous lumen through the steerable portion  102 , minimizing voids against which the end effector  250  ( FIG. 1 ) of the medical instrument can catch as it is distally advanced through the lumen into the body cavity. 
         [0031]    Pull elements (not shown) employed to steer the steerable portion  102  extend through guides  124  disposed on the exterior surface of the ball segment  120 . As described in the prior applications incorporated herein, the distal ends of the pull elements are coupled to the distal end of the steerable instrument channel, and the proximal ends are coupled to an actuator that applies/releases tension on the pull elements to steer the portion  102 . Examples of actuators that may be used to engage the pull elements are disclosed in the incorporated prior applications. 
         [0032]    The number of guides  124  used preferably corresponds to the number of pull elements that are to be used to steer the steerable portion  102 . Four guides  124  are shown spaced at 90 degree intervals, corresponding to the use of two or four pull elements. 
         [0033]    The vertebrae segments include anti-rotation features to prevent the segments  120 ,  122  from axially rotating relative to one another. As one example, anti-rotation members on one segment are engaged by anti-rotation features on the adjacent segments. In the drawings, the ball segments  120  have anti-rotation posts  126  that are received in corresponding receivers  128  extending proximally and distally from the socket segments  122 . 
         [0034]    Other deflectable shaft features that used in combination with the telescoping tip described herein are described in U.S. application Ser. No. 13/651,278, entitled Deflectable Instrument Shafts, filed Oct. 12, 2012, which is incorporated herein by reference. For example, a tubular liner of PTFE or other material may extend longitudinally through the lumen to form a smooth passageway for movement of instruments through the shaft. A skin formed of a thin flexible membrane or material may cover the segments to prevent surrounding body tissue or other material from passing into the spaces between adjacent segments, or from being pinched or captured between adjacent segments. The skin is preferably loose enough that it will not resist deflection of the shaft when the pull elements are actuated. 
         [0035]    During use of the first embodiment, the tip of the medical instrument (e.g. the end effector  250 ) is inserted into the proximal end of the lumen of instrument channel device  100 , advanced through the steerable portion  102  and into the telescoping reinforcement  104  which is in the nested configuration shown in  FIG. 2A . As the instrument tip exits the lumen at the distal end of the still-nested telescoping reinforcement, an engaging element on the instrument tip (e.g. on a portion of the end effector&#39;s clevis  251  or some other structure) contacts a stop on the innermost telescoping member  108   e.  The engaging element may also exist on the instrument shaft, more proximal to the instrument end effector to achieve additional instrument extension length. Continued advancement of the instrument tip distally pushes the member  108   e  sufficiently to overcome the engagement between the detent  112  of the member  108   e  and the deflecting members  114  of member  108   d,  and causes the telescoping member  108   e  to advance in a distal direction relative to the other members  108   a - 108   d . Once the detent  112  of member  108   e  reaches the distal end of the slot  110  of member  108   d,  member  108   e  can no longer move relative to member  108   d.  Thus continued advancement of the instrument tip overcomes the retention forces of member  108   c &#39;s deflecting members  114  on member  108   d &#39;s detents  112  and extends the member  108   d  distally relative to the members  108   a - 108   c.  Sequential extension of the members  108   b - e  of telescoping reinforcement  104  continues in this manner until the most proximal extendable member  108   b  is fully extended.  FIG. 2B  shows the end effector  251  on the instrument tip positioned distally of the telescoping reinforcement for use in a body cavity, with the telescoping reinforcement  104  fully extended such that it can prevent undesirable flexing of the portion of the instrument shaft that is distal to the steerable portion  102  of the steerable channel  100 . 
         [0036]    Features may be included for retracting the members  108   b - 108   e  in a proximal direction upon withdrawal of the instrument tip or end effector  250  from the telescoping reinforcement  104 . In one embodiment, a feature on the end effector  250  or clevis engages with a corresponding feature within member  108   e,  such that withdrawing the end effector in a proximal direction withdraws member  108   e  and then sequentially causes withdrawal of each of the more proximal members  108   d - 108   b.  In one embodiment, the engaging features are magnetic elements. For example, the stop within the distal end of member  108   e  may be a magnetic ring, and a component (e.g. a collar) on the instrument&#39;s clevis  251  is formed of a material that will magnetically engage with the magnetic ring. 
         [0037]    An alternative arrangement for withdrawing the telescoping reinforcement  104  utilizes a flat wire coil (or a circular cross-section extension spring) wound in a tubular configuration and having a first end coupled to the member  108   e  and a second end coupled more proximally, such as to member  108   a.  The coil may be positioned in the lumen of the telescoping reinforcement, or around the telescoping reinforcement&#39;s outer surface. In this embodiment, the coil is stretched when the telescoping reinforcement  104  is in the expanded position. When the end effector is withdrawn from the telescoping reinforcement  104 , the coil retracts and draws the members  108   b - 108   e  proximally into the collapsed position. It should be pointed out that the coil may apply sufficient retention forces to the members  108   b - 108   e  to prevent undesired expansion of the telescoping reinforcement  104 , thus eliminating the need for the deflecting members  114  described above. 
         [0038]    A flat wire coil of the type described in the prior paragraph may itself serve as a telescoping reinforcement, thus providing a telescoping reinforcement that will self-retract following withdrawal of the end effector, and that will remain biased in the nested configuration. As shown in  FIGS. 9A and 9B , this telescoping reinforcement  104   a  comprises a flat spring formed of a strip or ribbon of spring material, and having windings that extend in a longitudinal direction as shown. The spring has a nested configuration shown in  FIG. 9A . A stop within the lumen of the telescoping reinforcement  104   a  is coupled to the portion of the spring that forms the distal end of the telescoping reinforcement  104   a  when it is expanded. When the end effector of an instrument inserted into the instrument channel enters the telescoping reinforcement  104   a,  it engages the stop such that continued advancement of the end effector expands the reinforcement  104   a  to the  FIG. 9B  position. When force against the stop is released as a result of retraction of the instrument end effector, the spring retracts to the  FIG. 9A  position. It should be noted that the internalmost surface of the flat wire spring may engage with an insulating innermost member to prevent the spring from becoming hot while firing electro-cautery equipment inside the lumen. Additionally, the engagement feature on the flexible instrument may engage with the most proximal surface of the innermost wind on the flat wire spring. The innermost member against which the engagement feature exerts force to extend the spring may or may not be terminally bonded with the flat wire spring. The innermost member may allow be allowed to rotate inside the flat wire spring, to prevent undesirable torsion from being applied to the flat wire spring. Additionally, the engagement feature on the instrument end effector or shaft may be comprised of a bearing and shelf or other feature that allows smooth rotation of the instrument end effector or shaft without applying torsion to the innermost telescoping member. 
         [0039]    While certain embodiments have been described above, it should be understood that these embodiments are presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. This is especially true in light of technology and terms within the relevant art(s) that may be later developed. Moreover, features of the various disclosed embodiment may be combined in a variety of ways to produce additional embodiments. 
         [0040]    Any and all patents, patent applications and printed publications referred to above, including for purposes of priority, are incorporated herein by reference.