Abstract:
A sterile interface for a surgical platform is provided, optionally to be used with a mechanical telemanipulator. The sterile interface is configured to allow for transmission of motion without dimensional inconsistencies between a non-sterile surgical platform and a sterile surgical instrument that are related to one another in a master-slave configuration. The sterile interface is configured to allow for multiple changes of sterile surgical instruments during a surgical procedure without contaminating the sterile field. The sterile interface allows for interchangeable sterile articulated surgical instruments to be attached to the surgical platform without coming into contact with non-sterile portions of the surgical platform.

Description:
FIELD OF THE INVENTION 
       [0001]    A sterile interface for surgical instruments is provided. More particularly, a sterile interface is provided whereby a sterile instrument portion is attached or detached from a surgical device platform that is not in the sterile field. Even more particularly, the present invention relates to a sterile interface wherein articulated surgical instruments, which may be laparoscopic instruments, may be attached or detached from a surgical platform. The sterile interface allows for the rapid, easy, attachment and detachment of sterile articulated surgical instruments from a surgical platform several times during a surgical procedure, thus allowing the operator to use a multitude of surgical instruments during one procedure while maintaining a sterile surgical field, but while also not requiring the sterilization of the entire surgical platform. 
       BACKGROUND OF THE INVENTION 
       [0002]    Open surgery is still the standard technique for most surgical procedures. It has been used by the medical community for several decades and consists of performing the surgical tasks by a long incision in the abdomen or other body cavity, through which traditional surgical tools are inserted. However, due to the long incision, this approach is extremely invasive for the patient, resulting in substantial blood loss during the surgery and long and painful recovery periods in an in-patient setting. 
         [0003]    In order to reduce the invasiveness of open surgery, laparoscopy, a minimally invasive technique, was developed. Instead of a single long incision, one or more smaller incisions are made in the patient through which appropriately sized surgical instruments and endoscopic cameras are inserted. Because of the low degree of invasiveness, laparoscopic techniques reduce blood loss and pain while also shortening hospital stays. When performed by experienced surgeons, these techniques can attain clinical outcomes similar to open surgery. However, despite the above-mentioned advantages, laparoscopy requires advanced surgical skills to manipulate the generally rigid and long instrumentation through small incisions in the patient. 
         [0004]    Traditionally, laparoscopic instruments, such as graspers, dissectors, scissors and other tools, have been mounted on straight shafts. These shafts are inserted through small incisions into the patient&#39;s body and, because of that, their range of motion inside the body is reduced. The entry incision acts as a point of rotation, decreasing the surgeon&#39;s freedom for positioning and orientating the instruments inside the patient. Therefore, due to the drawbacks of currently available instrumentation, laparoscopic procedures are mainly limited to use in simple surgeries, while only a small minority of surgeons is able to use them in complex procedures. 
         [0005]    Laparoscopic instruments can be provided as disposable or reusable medical devices. Disposable devices are thrown away after each utilization, without having the need to be cleaned. On the other hand, reusable devices must be cleaned and sterilized after each procedure. In many instances, cost-effectiveness and operating room efficiency requires that instruments be cleaned, sterilized and re-used. 
         [0006]    Several laparoscopic instruments may be used during a single surgical procedure. For example, graspers, dissectors and scissors may all need to be used. The present Applicants have demonstrated the use of articulated laparoscopic surgical instruments in conjunction with a mechanical telemanipulator, which allows the surgeon to have control over the instruments with a master-slave configuration based upon mechanical transmission of the surgeon&#39;s hand movements to the surgical instruments at pre-determined levels of amplification. 
         [0007]    In this context, and in the context of other remotely actuated instrument systems, it is often desirable to detach and attach multiple instruments during a single procedure or period of operation. Particularly in the surgical context, although also when working in delicate, sensitive or contaminated environments, it is often desirable to create a sterile interface wherein the instruments being attached and detached are sterile but the platform to which they are attached is not in the sterile field. 
         [0008]    Prior examples of detachable sterile surgical instruments are known, but they have functional or dimensional drawbacks. In any remotely actuated system, the interface between sterile and non-sterile components must not only be designed in such a way as to maintain the sterility of, for example, the surgical instruments, but it must also provide a faithful transmission of motion from the remote actuator to the distally located instruments. Thus, each degree of freedom provided to the user of the remotely actuated system must be reproduced through transmission elements at the junction between the detachable instrument and the platform without dimensional inaccuracies or backlash. In addition, the connector element is often a single use or limited use product and so manufacturing costs should be relatively cheap. Prior interfaces, such as those shown in U.S. Pat. No. 7,699,855, have these known drawbacks due to their design elements, which typically transmit motion through reduced diameters and, thus, are susceptible to inaccuracies, backlash, other unwanted movements and incomplete transmission of motion. Prior interfaces, such as those found in U.S. Pat. No. 7,699,855 are limited-use and can only be taken through a certain number of sterilization cycles before becoming inoperative when connected with the surgical platform. 
         [0009]    Accordingly, an aim of the present invention is to overcome the aforementioned drawbacks of known devices by providing a sterile interface for remotely actuated surgical devices wherein sterile surgical instruments can be easily attached and detached from a non-sterile surgical platform. An additional aim is for the interface to provide faithful transmission of motion from the remote, non-sterile platform to the distally located sterile surgical instruments without dimensional inaccuracies or backlash. An additional aim is to provide single use interface elements that are inexpensive to manufacture but that nevertheless have tolerances that provide for the aforementioned faithful transmission of motion. An alternative aim is to provide interface elements that are relatively inexpensive to manufacture but are designed to be taken through multiple sterilization cycles without needing to be replaced, thus reducing overall operating room costs. 
       SUMMARY OF THE INVENTION 
       [0010]    These aims and other advantages are realized in a new sterile interface for the attachment of sterile surgical instruments to a non-sterile surgical platform. The sterile interface is intended to be used with articulated surgical instruments that are attached to a surgical platform. The surgical platform can be provided in the context of a mechanical telemanipulator. 
         [0011]    In various embodiments, the sterile interface can be used in connection with a mechanical telemanipulator with a master-slave architecture and a mechanical transmission system. This enables a natural replication of user hand movements on a proximal handle at end-effector elements. 
         [0012]    The sterile interface is designed such that surgical instruments, and in particular embodiments, laparoscopic surgical instruments, can be attached and detached from the mechanical surgical platform several times during a single surgical procedure. The sterile interface of the present invention is designed in such a way that sterilization is possible, allowing for several cycles of use before the interface elements need to be replaced. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0013]      FIG. 1  shows a mechanical telemanipulator with a detachable surgical instrument according to an embodiment of the present invention. 
           [0014]      FIG. 2  shows the kinematics of a mechanical telemanipulator with a detachable surgical instrument according to an embodiment of the present invention. 
           [0015]      FIG. 3  shows a surgical instrument detached from a mechanical telemanipulator according to an embodiment of the present invention. 
           [0016]      FIG. 4  shows the kinematics associated with a surgical instrument detached from a mechanical telemanipulator according to an embodiment of the present invention. 
           [0017]      FIG. 5  shows a detachable surgical instrument according to an embodiment of the present invention. 
           [0018]      FIGS. 6 through 11  show various articulated end-effector links in various positions according to various embodiments of the present invention. 
           [0019]      FIG. 12  shows the rotational elements of an interface portion of a surgical instrument according to an embodiment of the present invention. 
           [0020]      FIG. 13  shows the rotational kinematics of an interface portion of a surgical instrument according to an embodiment of the present invention. 
           [0021]      FIG. 14  shows a schematic view of the rotational elements of an interface portion of a surgical instrument according to an embodiment of the present invention. 
           [0022]      FIGS. 15 and 16  show the mechanical transmission elements of a mechanical telemanipulator in conjunction with a detached surgical instrument according to an embodiment of the present invention. 
           [0023]      FIG. 17 through 21  show various perspective views of an interface element in accordance with various embodiments of the present invention. 
           [0024]      FIGS. 22 and 23  show schematic views of kinematics associated with a mechanical telemanipulator according to an embodiment of the present invention. 
           [0025]      FIGS. 24 and 25  show perspective views of the attachment of elements of a surgical instrument to a surgical platform according to an embodiment of the present invention. 
           [0026]      FIG. 26  shows a perspective view of various elements of a fixation ring for attachment of a sterile cover according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    The sterile interface for articulated surgical instruments, according to an embodiment of the present invention, is intended to be used in a mechanical telemanipulator  1 , like the one shown in  FIG. 1 , whose kinematic model is shown in  FIG. 2 . One of the key features of this kind of mechanical telemanipulator  1  lies in a master-slave architecture and mechanical transmission system, which enable a natural replication of the user hand movements on a proximal handle  2 , by the end-effector  3  of a distal surgical instrument  4  on a remote location. 
         [0028]    The surgical instrument  4  can take different functions and forms, like a dissector, scissor or grasper and can be plugged and unplugged from the mechanical telemanipulator  1  several times during the same surgical procedure ( FIGS. 3 and 4 ). The remaining part of the mechanical telemanipulator  1 , excluding the surgical instrument  4 , is referred as the surgical platform  21 . It is desirable for the surgical instruments being plugged and unplugged to be sterile while the surgical platform is non-sterile. These plugging/unplugging procedures involve not only the structural attachment/detachment of the proximal part of surgical instrument  4  to the distal part of the surgical platform  21  but also the connection/disconnection of the mechanical transmission systems that deliver motion from the different articulations of the proximal handle  2  to the equivalent articulations of the end-effector  3 . In addition, these plugging/unplugging procedures have to be easily and quickly performed by the surgeons during the surgical procedure in order to avoid long and frustrating breaks in the surgeon&#39;s workflow. 
         [0029]    A surgical instrument  4  for minimally invasive surgical procedures, being able to be connected to an embodiment of the sterile surgical interface of the present invention, is described herein, and is seen generally in  FIG. 5 . This surgical instrument  4  includes a distal articulated end-effector  3 , a proximal hub  5  and a main shaft  6 , through which different mechanical elements  7 ,  8 ,  9  may pass, delivering motion to the different end-effector links  10 ,  11 ,  12  ( FIG. 6 ) from the proximal hub  5 . Referring to  FIG. 6 , the end-effector  3  is connected to the distal extremity of the main shaft  6  by a proximal joint, which allows the rotation of the proximal end-effector link  10  by the proximal axis  13  in such a manner that the orientation of the proximal end-effector link  10  with respect to the main shaft axis  14  can be changed. The distal end-effector links  11 ,  12  are pivotally connected to the proximal end-effector link  10  by two distal joints, having coincident axes of rotation, which are represented by the distal axis  15 . 
         [0030]    This distal axis  15  is substantially perpendicular and non-intersecting with the proximal axis  13  and substantially intersects the main shaft axis  14 .  FIGS. 7 to 11  show the surgical instrument  4  with different angular displacements at the end-effector joints. 
         [0031]    With reference to  FIGS. 12 and 13 , the movement is transmitted to each one of the three distal articulations of the instrument  4  by a rotating element  17 ,  18 ,  19 , which is able to rotate about an axis  20  and is connected to a transmission element  7 ,  8 ,  9 . As a result, when the rotating element  17 ,  18 ,  19  rotates a certain angle θ 1 , θ 2 , θ 3  about the axis  20 , a rotation α 1 , α 2 , α 3  is transmitted to the respective end-effector link  10 ,  11 ,  12 . Accordingly,  FIG. 14  shows how the movement is transmitted to the rotating elements  17 ,  18 ,  19  of the surgical instrument  4  from the distal part of the surgical platform  21 . The cylindrical elements  25 ,  26 ,  27 , which are mounted inside the housing element  23 , are able to translate along circular paths that are collinear with the axis  20 . When the proximal hub  5  is attached to the housing element  23 , the cylindrical elements  25 ,  26 ,  27  can be respectively connected to the rotating elements  17 ,  18 ,  19 , so that the movements generated at the handle  2  can be transmitted to the three end-effector links  10 ,  11 ,  12  by the transmission elements  7 ,  8 ,  9 . 
         [0032]    Since the surgical instrument  4  is entering the patient&#39;s body, it has to be sterile, just like the area in the vicinity of the patient. On the other hand, the surgical platform  21  is not sterile (and it is not desirable to have the entire surgical platform be part of the sterile field as this would not be practical in view of normal operating room workflow) and therefore should be separated from the sterile instrument portions by the sterile interface  28 , which protects the sterile area from the non-sterile components of the surgical platform  21  ( FIG. 15 ). 
         [0033]    The sterile interface  28  comprises two main components: a flexible sleeve  30 , which covers the moving links of the surgical platform  21  and a rigid connector  29 , which i) guarantees that the sterile instrument  4  is not directly touching non-sterile components, ii) enables attachment/detachment between the surgical instrument  4  and the surgical platform  21 , and iii) ensures the connection/disconnection of the mechanical transmission systems that deliver motion to the end-effector links  10 ,  11 ,  12 . Full connection of the mechanical transmission systems during operation of the platform is necessary for faithful replication of operator hand movements at the end effector. 
         [0034]      FIG. 16  shows an embodiment of the current invention where the sterile interface  28  comprises a plastic flexible sleeve  30  and a multi-component plastic rigid connector  29 . This plastic rigid connector  29  can be either sterilisable/reprocessable or single-use. However, in this particular embodiment, it is considered to be single-use, just like the plastic flexible sleeve  30 .  FIGS. 17 and 18  show different 3D views of the rigid connector  29 , with its multiple components  31 ,  32 ,  33 ,  34 ,  35 ,  36 ,  37 . The three miniature cups  32  are able to move along three circular grooves  32   a,  where they are inserted at the level of the insertion grooves  32   b.  The core component  31  has two surfaces  31   c  where the rings  33  and  34  can rotate, actuated by the compression springs  35  and  36 . The fixation ring  37  can be attached to the core component  31  by the deformation of the flanged surface  31   f  where the grooves  31   a  and the sharp points  31   b  are located. 
         [0035]      FIG. 19  shows how the rigid connector  29  can be positioned and operationally connected between the proximal hub  5  of the surgical instrument  4  and the housing element  23  of the surgical platform  21 . In order to connect/disconnect the mechanical transmission systems that deliver motion to the end-effector links  10 ,  11 ,  12  the cylindrical elements  25 ,  26 ,  27  are inserted on the three miniature cups  32 , which are then inserted on the rotating elements  17 ,  18 ,  19 . In this way, it can be guaranteed that the sterile surgical instrument  4  is not directly touching non-sterile components. Since the rigid connector  29  can be a single-use product, its manufacturing processes have to guarantee fairly low production costs, which typically cannot deliver very accurate components. Therefore, by transmitting the movement, through the miniature cups  32 , with translations on a maximized-diameter-circular path, this interface is less sensitive to dimensional inaccuracies or backlash between matching components. This is an improvement over other known devices where movement is transmitted by rotations with reduced diameters. A further advantage of this interface  28  pertains to its axisymmetric geometry, which is volumetrically optimized for rotations about the main shaft axis  14 . 
         [0036]    In another embodiment of the current invention ( FIG. 24 ), the miniature cups  32  don&#39;t need to be pre-inserted in the three circular grooves  32   a.  Instead, they have a geometry which enables them to be pre-inserted directly on the cylindrical elements  25 ,  26 ,  27  before the attachment of the core element  31  on the housing element  23 . As shown in  FIG. 25 , the miniature cups  32  can be attached directly to the cylindrical elements  25 ,  26 ,  27  thanks to their geometry, which comprises multiple longitudinal groves that enable the miniature cups to expand radially when the cylindrical elements  25 ,  26 ,  27  are inserted. Other solutions for the attachment of the miniature cups  32  on the cylindrical elements  25 ,  26 ,  27  can be used, using deformable components (like the one shown in  FIG. 25 ) or non-deformable components (for instance, using threaded surfaces, the miniature cups  32  can be screwed on the cylindrical elements  25 ,  26 ,  27 , or using magnets). 
         [0037]    The structural attachment/detachment between the surgical instrument  4  and the remaining part of the surgical platform  21  is made by inserting the five radially-displaced platform pins  24  in the five radially-displaced connector grooves  31   e.  On the surgical instrument  4  side, the five radially-displaced instrument pins  22  are inserted in the five radially-displaced connector grooves  31   d.  As can be seen in  FIG. 19 , these two attachment mechanisms, used to attach the rigid connector  29  on the surgical platform  21  and the surgical instrument  4  on the rigid connector  29 , have axi-asymmetric features or geometries (in the current embodiment, axi-asymmetric placement of radially-displaced pins and connector grooves) that prevent users from inserting the sterile articulated instruments on a wrong axial direction. 
         [0038]      FIG. 20  shows in detail the attachment mechanism between each instrument pin  22  and the respective connector groove  31   d.  When the instrument pin  22  enters the connector groove  31   d,  it touches the angular surface  34   a  of the ring  34 , causing its angular displacement against the compression spring  36 . This angular displacement allows the instrument pin  22  to reach the end of the connector groove  31   d,  where it is kept in place by the action of the compression spring  36 , whose force presses the angular surface  34   b  of the ring  34  against the instrument pin  22 . This sequence is simultaneously done at all the radially-displaced instrument pins  22 , guaranteeing the structural attachment between the surgical instrument  4  and the rigid connector  29 . The structural detachment between the surgical instrument  4  and the rigid connector  29  is achieved by the reverse sequence of actions. The structural attachment/detachment between the rigid connector  29  and the housing element  23  of the surgical platform  21  is performed in a similar interaction between each platform pin  24  and its respective connector groove  31   e.    
         [0039]      FIG. 21  shows how the flexible sleeve  30  can be releasably attached to the rigid connector  29 , by being squeezed between the flanged surface  31   f  of the core component  31  and the fixation ring  37 . The indentation of the sharp points  31   b  on the flexible sleeve  30  reinforces the attachment. This method of attachment is an improvement over prior art interfaces where the flexible sleeve  30  is glued or welded to the rigid connector  29 , which jeopardizes the possibility of having the flexible sleeve  30  as a single-use product and the rigid connector  29  as a reusable device. Therefore, with this feature in the interface as per the current invention, the rigid connector  29  can be cleaned and sterilized after each procedure, which can significantly reduce procedure costs over the use of prior art solutions. 
         [0040]    In another embodiment of the current invention ( FIG. 26 ), the fixation ring  37  may be fixed to a rotating ring  38 , which is able to freely rotate around the core component  31 . In this embodiment, the flexible sleeve  30  is squeezed between the fixation ring  37  and the rotating ring  38  and its torsional deformation is minimized when the core component  31  is rotated around the axis  20  by the platform  21 . 
         [0041]    While this invention has been shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. For instance, the mechanical telemanipulator  1  can assume other kinematics, like the ones shown in  FIGS. 22 and 23 . In addition, while the sterile interface of the present invention has been primarily described in connection with a laparoscopic surgical platform, one of skill in the art will understand that the sterile interface could easily be used with other surgical platforms, such as open field systems. In addition, the current sterile interface could be used with other telemanipulator or remote actuation systems in other sterile situations outside of the surgical context.