Abstract:
A collapsible scaffolding can collapse for deployment to a laparoscopic surgical site through a trocar or the like, and can expand to provide a surface for organ retraction within a body cavity. In the expanded state, the scaffolding may assist a surgical procedure in a variety of ways, such as by providing a rigid structure upon which to secure retracted organs or surgical tools such as lights, cameras, and so forth.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional App. 61/671,140, filed Jul. 13, 2012, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Laparoscopic surgery involves creating one or more relatively small incisions in a subject that provide a surgeon&#39;s tools with access to a surgical site. Laparoscopic surgery enjoys certain advantages over more invasive procedures because the small surgical incisions often require less time to heal, are less painful, and leave smaller scars. On the other hand, in these minimally invasive techniques a surgeon generally operates in a highly constrained space within a patient&#39;s body such as the abdominal cavity. 
     Moreover, inside the abdominal cavity, organs and other tissue may obstruct access to a surgical site. For example, with a patient lying supine on an operating table, the patient&#39;s liver typically covers the gallbladder. Thus, laparoscopic procedures on a gallbladder often involve a precursor step of moving and securing the patient&#39;s liver away from the surgical site. This typically requires an additional person to manipulate the liver during the procedure and perform related tasks such as manipulating a light or camera, which can further limit the surgeon&#39;s working space inside and outside the abdominal cavity. 
     There remains a need for improved surgical tools to simplify laparoscopic surgical procedures. 
     SUMMARY 
     A collapsible scaffolding can collapse for deployment to a laparoscopic surgical site through a trocar or the like, and can expand to provide a surface for organ retraction within a body cavity. In the expanded state, the scaffolding may assist a surgical procedure in a variety of ways, such as by providing a surface to manually expand the cavity, or by providing a rigid structure upon which to secure retracted organs or surgical tools such as lights, cameras, and so forth. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention and the following detailed description of certain embodiments thereof may be understood by reference to the following figures: 
         FIG. 1A  is a perspective view of a surgical scaffold in a deployed state. 
         FIG. 1B  is a perspective view of a surgical scaffold in a partially deployed state. 
         FIG. 1C  is a perspective view of a surgical scaffold in an undeployed state. 
         FIG. 2  is a schematic view of a flexural structure. 
         FIGS. 3A and 3B  are a perspective view of a surgical scaffold with a retaining member. 
         FIG. 4  is a schematic view of a surgical scaffold with additional elements. 
         FIG. 5  is a schematic view of a surgical scaffold deployed during a surgical procedure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, references to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the context. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Thus the term “or” should generally be understood to mean “and/or” and so forth. 
     Terms of degree, such as “about” or “substantially” are intended to contemplate a range of values within the ordinary variability expected by one of ordinary skill in the art and suitable for the uses contemplated herein. 
     Among other things, disclosed herein are various embodiments of a surgical scaffold device that can be deployed in a laparoscopic procedure. Among other advantages, the scaffold helps mitigate some of the difficulties associated with certain laparoscopic procedures discussed above. 
       FIG. 1A  is a perspective view of a surgical scaffold in a deployed state. The scaffold  100  may include a primary member  102  having a front end  104  and a back end  106 . As used herein, the terms “front” and “back” are arbitrary terms employed for convenience only. These terms are not intended to convey any preferred orientation, function, or structure, or to suggest any intrinsic difference or similarity between the ends of the scaffold, or any other components referred to herein as “front” and “back” components. While certain differences may be noted below, these are provided only by way of exemplary embodiments and are not intended to limit the meaning of the terms “front” and “back” as described above. Similarly, terms such as “top” and “bottom” are provided for convenience only, and are not intended to convey any specific orientation, function, or structure unless explicitly noted to the contrary or otherwise clear from the context. 
     The primary member  102  may be coupled to lateral support members  111  by one or more front hinges  108  and back hinges  110 . The hinges  108 ,  110  may, for example, be barrel hinges, pivot hinges, mortise hinges, flexural hinges, or any other type(s) of hinges suitable for use in a surgical device. The hinges  108 ,  110  may be integrally formed into the material of the primary member  102  and lateral support members  111  where these members meet, or the hinges  108 ,  110  may be separate mechanical components attached as appropriate to these members. In order for the scaffold  100  to deploy into a resilient working surface, the hinges  108 ,  110  may collectively articulate in a plane of articulation that contains the scaffold  100  (if the scaffold is not flexed, as described below). That is, the hinges  108 ,  110  may constrain motion of the connected elements so that they remain within a plane formed by the deployed scaffold  100 , or stated alternatively, the hinges  108 ,  110  may rotate about an axis perpendicular to the plane formed by the deployed scaffold  100 . 
     A lateral support member  111  may be rotatably coupled to the primary member  102  at each hinge  108 ,  110 . Ancillary members  112  may be rotatably coupled to the lateral support member  111  by hinges  113 . Although  FIG. 1A  shows two ancillary members  112 , in principle any number of ancillary members may be employed. The terms “primary” and “ancillary” are terms of convenience only; there need not be any structural differences (or similarities) between primary and ancillary members, except in certain embodiments as noted below. The term “axial member” is used to collectively refer to either the primary or any ancillary member. 
     The primary member  102  and ancillary members  112  may include one or more flexural structures  114 . The flexural structures  114  may be any structure(s) that allow a member to flex in a direction outside the plane of the scaffold. The flexural structures  114  may be advantageously constructed, e.g., as shown below, to facilitate planar deflection of the scaffold  100  while inhibiting in-plane movement (e.g., lateral displacement) of the individual axial members. Any suitable flexural structure  114  may be used, including but not limited to hinges, springs, or the like. Further details of some flexural elements suitable for use as the flexural structures  114  of the scaffold  100  are provided below. 
     The “deployed” state is characterized by the distances  116   a, b  between the primary member  102  and the ancillary members  112  being maximized, or more generally greater than a partially deployed or undeployed state. 
       FIG. 1B  is a perspective view of the surgical scaffold in a partially deployed state. In general, the hinges described above facilitate a range of in-plane movements of the axial members of the scaffold  100  relative to one another between an undeployed state and a deployed state. A “partially deployed” state may be any relative position of the axial members characterized by at least one inter-member distance  116  between an ancillary member  112  and the primary member  102  being greater than in the undeployed state and less than in the deployed state. More specifically as depicted, one ancillary member  112  is fully collapsed and in contact with the primary member  102 , while a second ancillary member  112  is partially collapsed 
       FIG. 1C  is a perspective view of the surgical scaffold in an undeployed state characterized by a minimized distance between the primary member  102  and the ancillary members  112 . Although  FIG. 1C  shows an undeployed state with a minimized distance of zero—i.e., the members are in contact—in general this contact need not occur in an undeployed state. 
     In some uses, the scaffold  100  may be inserted into a patient&#39;s body through a trocar. Thus, in the undeployed state, the maximum cross-sectional distance across the scaffold  100  in a plane perpendicular to the axes of the members  102 ,  112  may be small enough to fit through such a trocar. Trocars in common use today may have inner diameters of approximately 10-15 mm, and the undeployed scaffold  100  may correspondingly have a cross section (perpendicular to the axis of the primary member  102 ) with a diameter of about 10-15 mm. In one aspect, the cross-sectional form of the ancillary members may be rounded or otherwise shaped to fit within a trocar barrel. 
     In some implementations, the length of scaffold  100  in the undeployed state may be long enough to fulfill the functions described herein, but not so long as to pose a safety risk to the patient during insertion through the trocar. In some implementations, the length of the scaffold  100  in its deployed state may be about eight inches, or between about seven inches and about ten inches. The ancillary members may be any suitable length, such as between about one inch and about two inches. 
     The scaffold  100  may be constructed of any material or combination of materials suitable for insertion into a living patient. This may include, for example, alloys such as surgical stainless steel, shape memory alloys, polymers, plastics, or the like. In one aspect, the scaffold  100  may be formed of relatively inexpensive materials such as a biocompatible polymer for use as a disposable surgical tool. In another aspect, the scaffold  100  may be formed of a surgical stainless steel or other autoclavable material suitable for repeated use. 
       FIG. 2  is a schematic view of an exemplary flexural structure. The flexural structure  200  is shown relative to an axis L of the axial member that incorporates the flexural structure  200 . 
     The flexural structure  200  may include axial protrusions  202   a, b, c, d  that extend axially toward one another without contacting one another when the flexural structure  200  is unflexed. The axial protrusions  202   a ,  202   b  may form a top layer that defines a top gap  204 . Similarly, the axial protrusions  202   c ,  202   d  may form a bottom layer that defines a bottom gap  206 . In general, the dimensions of the protrusions  202   a ,  202   b ,  202   c ,  202   d  (and therefore, the dimensions of the top and bottom gaps) need not be identical. 
     The flexural structure  200  may also include a middle layer  208 . The middle layer may include a flexible region  210 . Although shown schematically as a line in  FIG. 2 , the flexible region  210  may extend throughout the entire middle layer  208 , or any subset thereof. The middle layer  208 , and more generally, the flexible structure  200 , may be formed from any resilient material suitable for insertion into a living patient, including the materials described above. In some implementations, the middle layer and/or flexible region may be relatively narrow, thereby providing sufficiently low stiffness to allow a desired degree of flexure. Similarly, the thickness of the middle layer  208  may depend upon the desired stiffness of the flexural structure  200 , the material from which the flexural structure  200  and/or middle layer  208  are formed, and any other appropriate design constraints. For example, for a particular, predetermined stiffness, a substantially thicker middle layer  208  may be required if the middle layer  208  is formed from a medical grade polyurethane rather than surgical stainless steel. 
     When flexure-inducing forces are applied to the flexural structure  200 , for example in the directions D 1  and D 2  shown in  FIG. 2 , the ends of the structure  200  will deflect, and the middle layer will flex, e.g. at the flexible region  210 . As the flexural structure  200  continues to flex, one of the gaps  204  and  206  may shrink. For example, when the ends of the structure  200  move in the directions D 1  and D 2 , the top gap  204  tends to close. If enough flex-inducing force is applied, then eventually an opposing pair of the protrusions  202   a - d  may come in contact, and the gap they define may disappear. In this state, the contact between the protrusions tends to inhibit any further flexure of the flexural structure  200 . Thus, upward or downward flexural limits may be individually implemented at various points along the axial members by choosing the size of the top or bottom gaps  204 ,  206  at those points. 
     In some implementations, it may be desirable for the scaffold  100  to conform to the curved wall of a typical human&#39;s abdomen. As such, the flexural structures  200  may be shaped and sized to accommodate a corresponding deflection in the axial members of a scaffold. In some implementations, the axial members may be configured using the flexural structures  200  to permit an end-to-end deflection of some predetermined angle, such as five degrees or less, but to inhibit end-to-end deflection greater than the predetermined angle. It is within the ordinary skill in the art to determine shapes and sizes of the protrusions and gaps in each flexural structure  200  to accommodate this predetermined flexing behavior, and the variations and details are omitted here. In some implementations, an axial member may include flexural structures  200  and gaps/protrusions at predetermined intervals (e.g., at a pitch of one inch) or of a predetermined number to create a desired flexing behavior of the axial member(s). 
       FIG. 3A  is a perspective view of a surgical scaffold with a retaining member. The scaffold  300  may include a primary member  302  and ancillary members  312  as described above. The scaffold  300  may also include a coupling  314  such as a through-hole with one or more coupling or registration features to removably and replaceably receive a retaining member  316  in a manner that facilitates manipulation of the scaffold  300  with the retaining member  316 . Although the coupling  314  is shown in the primary member  302 , in principle the coupling  314  can be located anywhere on the scaffold  300 . 
     A separate retaining member  316  may also be provided. As described below, the retaining member  316  may be operable to help keep the scaffold  300  in place while the scaffold is deployed within a patient. The retaining member  316  may include a coupling  318  at its distal end that is configured to mate with the coupling  314  on the scaffold  300 .  FIG. 3B  shows the retaining member  316  coupled to the scaffold  300  via the couplings  314  and  318  (not shown). 
     When the retaining member  316  is coupled to the scaffold  300 , the couplings  314 ,  318  may be configured to allow the retaining member  316  to provide the scaffold with torque, a normal force, and an in-plane force in at least some directions. In this context, “normal” connotes the direction perpendicular to the plane of the scaffold, and “in-plane” connotes a direction parallel to the plane of the scaffold. In some implementations, applying force in certain in-plane directions is operable to disengage the retaining member  316  from the coupling  314 , but force in other in-plane directions is operable to transfer such force to the scaffold  300 . In some implementations, through a combination of applied normal and in-plane forces, the retaining member  316  may transfer a retaining force to the scaffold. “Retaining force” connotes force in a direction that is counter to the load on the scaffold  300  by an organ retained thereon. Thus, by application of a retaining force, the retaining member  316 , may permit a surgeon to lift or otherwise retract an organ from a surgical site within an abdominal cavity. 
     The retaining member  316  may be inserted through the patient&#39;s abdominal cavity to engage the scaffold  300  once the scaffold has been deployed within the cavity. In some implementations, the retaining member  316  has a cross-sectional area small enough to minimize scarring in the resultant puncture. In some implementations, the retaining member  316  may have maximum cross sectional distance less than two millimeters. 
     In some implementations, the couplings  314 ,  316  may also include an electrical coupling. The electrical coupling may be operable to provide power or control signals from an external source to additional elements on the scaffold  300 , as described more fully below. In some implementations, one or more electrical couplings can be located elsewhere on the scaffold  300 . In some implementations, the electrical couplings can receive power or control signals through one or more wires fed through the insertion trocar. 
       FIG. 4  is a schematic view of a surgical scaffold with additional elements. The additional elements described below may be useful during some laparoscopic procedures. 
     The scaffold  400  may have a short ancillary member  404  and a long ancillary member  406  so that the scaffold deploys in the shape of a trapezoid. This may be advantageous when an anticipated use of the scaffold  400  involves positioning it with one end (e.g., the short end) in a relatively small space, such as abutting the patient&#39;s diaphragm. More generally, the scaffold  400  can include ancillary members having different dimensions that result in any other perimeter geometry that conforms to an anticipated deployment site. 
     The scaffold  400  may include a mesh  408  deployed between two members. The mesh  408  may advantageously help retain some of the patient&#39;s anatomical structures in a safe location during the surgical procedure. The mesh  408  may be constructed from any suitable biocompatible material, including polymer threads such as nylon or polyester, natural threads such as silk, or the like. Although the mesh  408  is shown in only a portion between the members  402  and  406 , in principal the mesh  408  can extend throughout the entire space between any two members, or any portion thereof. 
     The scaffold  400  may include one or more light sources  410 , including but not limited to light emitting diodes (LEDs). The light source  410  may provide illumination to the surgical site. Moreover, using more than one light source  410  may mitigate the effect of shadows and reduce the chances of obstructing illumination with the movement of surgical instruments. As such, the scaffold  400  may include two light sources, three light sources, or any other number of light sources suitable for illuminating surfaces of interest in a surgical procedure. In some implementations, the light sources  410  may be provided with power and/or control signals from an external source via the retaining member through an electrical coupling  411 . 
     The scaffold  400  may include one or more loops  412 . The loops  412  may advantageously serve as tie points that can be used to anchor organs or other surgical tools to the scaffold  400  using surgical thread, clamps, or the like. Similarly, the scaffold  400  may include one or more hooks  414  or clamps  415  that may be similarly employed to secure tissue or surgical instruments as appropriate. 
     The scaffold  400  may include a high-friction surface (e.g., the top side or a portion thereof), such as a textured or knurled surface, that may help promote organ retention. The top side of the scaffold  400  may also or instead include one or more regions having a relatively soft or pliable coating to mitigate irritation to the patient&#39;s abdominal wall or diaphragm from the scaffold  400 . The pliable coating may include any soft surgical material, such as rubber, silicone, other elastomers, or the like. 
     The scaffold  400  may include one or more magnets  416 . The magnets  416  may include permanent magnets or electromagnets. In embodiments involving electromagnets, the electromagnets  416  may receive power and/or control signals from an external source via the retaining member through an electrical coupling  411 . The magnets  416  may advantageously provide locations to easily and securely place magnetic surgical tools or other magnetic materials. 
     The scaffold  400  may include one or more video cameras  418 . The video camera(s)  418  may receive power and/or control signals from an external source via the retaining member through an electrical coupling  411 . The video camera(s)  418  may also send a video signal to an outside receiver through the electrical coupling, or the video camera(s)  418  may transmit video wirelessly using, e.g., radio frequency communications. The video camera(s)  418  may be movably connected to the scaffold  400 , such as by removably and replaceably coupling a video camera  418  to the scaffold  400 , or by including a universal joint or the like in a mechanical coupling from the video camera  418  to the scaffold  400 . In this manner, the field of view of one of the video cameras  418  may be adjusted during the surgical procedure. In some implementations, two or more cameras  418  may be mounted on the scaffold  400  such that every camera has a field of view that overlaps with the field of view of at least one other camera. 
       FIG. 5  is an exemplary schematic cross-sectional view of a surgical scaffold deployed in a human patent during a surgical procedure. In this example, the scaffold  500  is deployed within the abdominal cavity  502  defined in part by the patient&#39;s abdominal wall  504 . An obstructing organ  508  (e.g., the liver) is secured to the platform  500  by any of the techniques described above, thus exposing the surgical target  510  (e.g., the gallbladder). Thus, a surgeon may access the surgical target  510 . Moreover, the overhead clearance of the surgical target  510  is relatively well utilized, inasmuch as the scaffold  500  substantially conforms to the patient&#39;s abdominal wall  504 . Although  FIG. 5  shows a gap between the scaffold  500  and the abdominal wall  504 , this has been shown for clarity. The scaffold  500  may contact the abdominal wall  504  to a substantial degree, such as where the scaffold  500  is also used to lift the abdominal wall  504  away from the surgical site. 
     The scaffold  500  is held in place by a retaining member  512 . In some implementations, the retaining member  512  may be further stabilized with support structures  514  that mechanically couple the retaining member to the patient. In some implementations, the retaining member  512  may be further stabilized via a mechanical coupling to an external support  516 . The external support  516  may include any manner of structures—e.g., clamps, graspers, vices, magnets, actuators, etc.—that may be collectively operable to hold the retaining member  512  in a fixed or otherwise controllable position. 
     While the invention has been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law.