Abstract:
A torque-transmitting, variably-flexible insertion device includes a hollow body having a proximal end with an entrance for receiving an instrument and a distal end with a tip for protrusion of the instrument. A vacuum-activated device transitions the hollow body between a relatively flexible condition and a relatively stiff condition. A torque braid transmits torque from the proximal end toward the distal end. A method for transmitting torque and variably flexing the insertion device includes transmitting torque along the hollow body with the torque braid, applying suction to create a vacuum in the hollow body for placing the hollow body in the relatively stiff condition, and relieving the vacuum for placing the hollow body in the relatively flexible condition.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority, under 35 U.S.C. §119(e), of provisional application No. 60/802,466, filed May 22, 2006; the prior application is herewith incorporated by reference in its entirety. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a torque-transmitting, variably-flexible insertion device. The invention also relates to a method for transmitting torque and variably flexing an insertion device. 
         [0004]    2. Description of the Related Art 
         [0005]    Insertion devices for surgical instruments are known in the art. Such devices include those which can transition between a relatively stiff and a relatively flexible condition, such as that disclosed in co-pending U.S. patent application Ser. No. 11/367,607, filed Mar. 2, 2006 and naming the inventors of the instant application. 
         [0006]    A disadvantage of such variably flexing insertion devices is that the device twists when applying torque to the proximal end and therefore the torque is not transmitted along the device toward the distal end. This makes it difficult or impossible to impart a circumferential movement along the device when needed to traverse the body. 
       SUMMARY OF THE INVENTION 
       [0007]    It is accordingly an object of the invention to provide a torque-transmitting, variably-flexible insertion device and a method for transmitting torque and variably flexing an insertion device, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and which transmit torque from the proximal end toward the distal end of the device. It is a further object of the invention to provide a simple yet effective measure for steering the insertion device. 
         [0008]    With the foregoing and other objects in view there is provided, in accordance with the invention, a torque-transmitting, variably-flexible insertion device, comprising a hollow body having a proximal end with an entrance for receiving an instrument and a distal end with a tip for protrusion of the instrument. A vacuum-activated device transitions the hollow body between a relatively flexible condition and a relatively stiff condition. A torque braid transmits torque from the proximal end toward the distal end. 
         [0009]    With the objects of the invention in view, there is also provided a method for transmitting torque and variably flexing an insertion device for receiving an instrument. The method comprises providing a hollow body, transmitting torque along the hollow body with a torque braid, applying suction to create a vacuum in the hollow body for placing the hollow body in a relatively stiff condition, and relieving the vacuum for placing the hollow body in a relatively flexible condition. 
         [0010]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0011]    Although the invention is illustrated and described herein as embodied in a torque-transmitting, variably-flexible insertion device and a method for transmitting torque and variably flexing an insertion device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0012]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a diagrammatic, side-elevational view of a steerable, variably-flexible insertion device according to the invention, which has been steered to the right; 
           [0014]      FIG. 2  is a view similar to  FIG. 1 , of the insertion device steered to the left; 
           [0015]      FIG. 3  is a perspective view of the insertion device of  FIGS. 1 and 2 ; 
           [0016]      FIG. 4  is a fragmentary, side-elevational view of a steering assembly of the insertion device of the invention; 
           [0017]      FIG. 5  is a perspective view of a stiffness zone assembly of the insertion device of the invention; 
           [0018]      FIG. 6  is a longitudinal-sectional view of a sliding tire valve and side tube assembly of the insertion device of the invention; 
           [0019]      FIG. 7  is an elevational view of an ergonomically constructed valve handle to be used with the insertion device of the invention; 
           [0020]      FIG. 8  is a longitudinal-sectional view of the handle of  FIG. 7 ; 
           [0021]      FIG. 9  is an elevational view of a torque braid of the insertion device of the invention; 
           [0022]      FIG. 10  is an enlarged, fragmentary, perspective view of the torque braid between an outer jacket and an inner sleeve covering a coil of the insertion device; 
           [0023]      FIG. 11  is a fragmentary, perspective view showing tendons intermittently woven through the torque braid; and 
           [0024]      FIGS. 12 ,  13 ,  14  and  15  are cross-sectional views of the insertion device of the invention, which are taken along a line XII-XV of  FIG. 2 , in the direction of the arrows, but with the torque braid in various locations. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    Referring now to the figures of the drawings in detail and first, particularly, to  FIG. 1  thereof, there is seen a steerable, variably-flexible insertion device  1  according to the invention. The insertion device  1  has a hollow body with a proximal end  2  for manipulation by an operator and for receiving an instrument such as an endoscope or a colonoscope. The insertion device  1  also has a distal end  3  for insertion into a patient and for protrusion of the instrument. A handle  4  of the hollow body for control by the operator is disposed at the proximal end  2 . The handle  4  has a vacuum connection or nipple  5  for controlling stiffness of the device, as will be explained below. An outer jacket  41  of the hollow body, which is disposed between the handle  4  and a tip  7  of the hollow body at the distal end  3 , is not shown in  FIG. 1 . The outer jacket  41 , which is shown in  FIG. 10 , provides a flexible section with a given length extending beyond the handle  4 . Whereas  FIG. 1  shows the hollow body steered to the right,  FIG. 2  shows it steered to the left and  FIG. 3  shows the hollow body in perspective. 
         [0026]    A steering assembly  10  of the device  1  includes five vertebrae  13 - 17  shown as being disposed along the hollow body. However, more or fewer vertebrae can be provided in dependence on the length, diameter and use of the hollow body. Eight tendons are shown as being equally spaced apart about the circumference of the hollow body. A first four of those tendons, identified as non-steering tendons and indicated by reference numeral  11 , extend only between the handle  4  and the vertebra  17  where they are fixed in place. A second four of those tendons, identified as steering tendons and indicated by reference numeral  12 , are spaced apart by 90° circumferentially and extend between the handle  4  and the distal-most vertebra  13  where they are fixed in place. Once again, a greater or lesser number of tendons may be used, as needed. The tendons may have a rounded or flattened cross section or a flattened cross section twisted along its length. The vertebrae to which the tendons are fixed may be referred to as weld rings since the tendons may be welded thereto. For example, all of the tendons  12  are fixed to the vertebra  13 , such as by welding. At the vertebra  16 , for example, the steering tendons  12  are permitted to slide, but the non-steering tendons  11  are welded or otherwise fixed in place. When welding is used for fixation, the tendons and vertebrae are normally made of stainless steel. However, the tendons and vertebrae may also be formed of plastic which is bonded or adhesively connected where desired. Both metal and plastic tendons and vertebrae may be used in one device. 
         [0027]    Four knobs  6  are each slideably disposed within a respective slot  8  in the handle  4 . Each of the steering tendons  12  extend between the vertebra  13  and a respective one of the knobs  6 . Each steering tendon  12  extends through a respective knob  6  and is connected to a respective stop  9 . When a knob  6  is slid proximally, it pushes a stop  9  and pulls a steering tendon  12  to steer the hollow body. In the condition shown in  FIG. 1 , the knob  6  at the right has been slid proximally so that the tip  7  of the hollow body has been steered to the right. In the condition shown in  FIG. 2 , the knob  6  at the left has been slid proximally so that the tip  7  of the hollow body has been steered to the left. A similar result shown in  FIG. 3  has been accomplished by sliding one of the knobs  6  proximally. When the knobs  6  are forced distally, the knobs can freely slide independently of the steering tendons  12  to prevent buckling of the steering tendons  12 . It will be readily understood that if two of the knobs are slid proximally, the tip  7  will move in a direction between the two directions that each one of the knobs would have moved the tip if moved individually.  FIG. 4  shows the device  1  with the handle  4  removed, from which it can be seen that the steering tendons  12  of the steering assembly  10  continue toward the handle from the tip  7 , whereas the non-steering tendons  11  stop. 
         [0028]    It is also possible, as shown in  FIG. 5 , to provide stiffness zones within the steering assembly  10 . For example, a stiffness zone A closest to the distal tip  17  has four tendons, a stiffness zone B has eight tendons and a stiffness zone C closest to the handle  4  has sixteen tendons. A zone with more tendons will be stiffer than a zone with fewer tendons. The number of tendons and their location within the zones as well as the number of zones can be increased or decreased, depending on the application of the device. The vertebrae are also shown. The four tendons in the zone A are all fixed at the upper most vertebra but are free to slide elsewhere. Four of the eight tendons in zone B, which do not extend to zone A, are fixed at the vertebra between zones A and B but are free to slide elsewhere. Similarly, eight of the sixteen tendons in zone C, which do not extend into zones A and B, are fixed at the vertebra between zones B and C but are free to slide elsewhere. 
         [0029]      FIG. 6  shows a cross-sectional view of the handle  4  of  FIGS. 1-3 , in which the connection or nipple  5 , knobs  6  and slots  8  are not shown. The handle  4  has an inner handle  19  disposed within an outer handle  18 , defining an annular vacuum plenum volume  24  therebetween which extends in longitudinal direction of the handle  4 . A vacuum inlet/outlet hole or port  25  is formed in the body of the outer handle  18  and communicates with the volume  24 . A sliding so-called tire valve thumb grip  20  encircles the outer handle  18  and is sealed thereto by O-ring seals having O-rings  21  in recesses  22  in the grip  20 . The grip  20  also has a vacuum inlet/outlet  23  for the connection or nipple  5 . When the grip  20  is slid toward an annular stop  26  as shown, the vacuum inlet/outlet  23  is not in alignment with the vacuum inlet/outlet hole  25 . However, when the grip  20  is slid toward an annular stop  27 , the vacuum inlet/outlet  23  and the vacuum inlet/outlet hole  25  are aligned, providing communication between the connection or nipple  5  and the volume  24 . Therefore, during operation, the grip  20  is slid toward the stop  27  to apply vacuum to stiffen the hollow body or to vent the vacuum to the atmosphere or supply air at atmospheric pressure to make the hollow body flexible again. The grip  20  is slid toward the stop  26  to maintain the stiffened or flexible condition of the hollow body attained by vacuum or venting or air supply through the connection or nipple  5 . 
         [0030]    An end cap  28  is inserted into a proximal end of the outer handle  18  for insertion of an instrument, such as an endoscope or a colonoscope. End caps with various sized openings may be used in dependence on the instrument being used. The instrument passes through the hollow body and emerges at the distal tip  7 . A diaphragm seal or so-called septum  29  is disposed between the end cap  28  and the inner handle  19 . A dot-dash line  30  represents an instrument inserted through the handles. 
         [0031]      FIGS. 7 and 8  show a handle  4  with an outer vacuum valve handle  35  which is ergonomically configured with a so-called handlebar shape to be gripped by the hand of an operator of the device. A tire valve thumb grip  20  as is seen in  FIG. 6  is also provided in the embodiment of  FIGS. 6 and 7 , but has been omitted for clarity. The outer handle  35  is an alternative to the outer handle  18 . As can be seen from the cross section of  FIG. 8 , a vacuum source may be connected to a port  36  in the outer handle  35  and the vacuum inlet/outlet  23  of the tire valve thumb grip  20  may communicate with a vacuum inlet/outlet hole  37  leading to an annular vacuum plenum volume  39  between the outer handle  35  and an inner handle  38 . When the tire valve thumb grip  20  is slid so that the vacuum inlets/outlets  23  and  37  are misaligned, vacuum is supplied from the port  36  to the vacuum plenum volume  39 . When the tire valve thumb grip  20  is slid so that the vacuum inlets/outlets  23  and  37  are aligned, the plenum  39  is vented to the atmosphere. An end cap  34  is also shown. 
         [0032]      FIG. 9  illustrates a torque sheath or braided inner liner  40  of the insertion device  1 . The torque braid  40  is a woven tube formed of fabric, plastic, metal or a combination thereof, such as a metallized material. Steel or a polymer, such as polyethylene terephthalate or PET (sold under the trademark MYLAR) or PEEK (polyether ether ketone) are particularly useful. The purpose of the torque braid  40  is to transmit torque applied by the operator of the device at the proximal end  2  along the length of the hollow body up to the tip  7 . Therefore, the torque braid must be non-linearly compliant, that is it has a limited elongation in the linear direction. 
         [0033]    As is shown in the perspective view of  FIG. 10 , the torque braid  40  may be disposed in a space  44  between an outer jacket  41  and an inner sleeve  42 . In the illustrated embodiment, the torque braid  40  is disposed above the vertebra  15 , but the tendons have been omitted for clarity. The torque braid  40  may be placed in various locations, as will be described below with reference to  FIGS. 12-15 . The purpose of the torque braid  40  is to allow twisting of the hollow body as well as steering of the hollow body by the tendons while inserting the insertion device into the body. The torque braid  40  is typically provided over the full length of the hollow body, but may also be omitted at the tip  7  for additional flexibility or doubled, for instance, near the handle  4  for additional stiffness. 
         [0034]      FIG. 10  also shows a coil  43  of the hollow body which is provided within the inner sleeve  42  of the hollow body for supporting the inner sleeve. The coil may be a wire which is TEFLON- or hydrophilic-coated to ease insertion of an endoscope or colonoscope. The stiffness or spring constant k of the coil  43  tends to maintain the device  1  in a straight condition and is used to maintain the round cross section of the device  1  while it is flexed. 
         [0035]      FIG. 11  shows an alternative embodiment of the torque braid  40  and the tendons  11 ,  12 , in which the tendons are intermittently woven through the torque braid to eliminate the need for the vertebrae  13 - 17 . The tendons  11 ,  12  travel under the torque braid  40  for about 2 inches and then are woven through one loop of the torque braid  40  to create weave points. This is repeated along the length of the device. The weave points act like the vertabrae in “attaching” the tendons  11 ,  12  to the body of the device but letting the tendons slide through. Using the torque braid in this way eliminates the need for the vertabrae thus decreasing the outer diameter of the device, lowering the cost of the device and simplifying the structure thereof. It is noted that the tendons are shown as being flexed as they weave through the torque braid for clarity of the illustration. In actuality there will be some amount of flex in both the torque braid and the tendons, but mostly on the part of the torque braid. The tendons could also be woven in the opposite way, that is laid on top of the braid and woven down into it. 
         [0036]      FIGS. 12-15  are cross-sectional views of the device, in which the torque braid  40  is placed in various locations. In each of the figures, as seen from the exterior toward the interior, the insertion device  1  includes the outer jacket  41 , the space  44 , the vertebrae  13 - 17  (reference numeral  15  is used as an example), the inner sleeve  42  and the coil  43 , although the latter is merely shown in outline form for the sake of clarity. It is also seen that the vertebrae  13 - 17  have channels  45  formed therein permitting movement of the tendons  11 ,  12  which are not fixed in place. 
         [0037]    In the embodiment of  FIG. 12 , the torque braid  40  is disposed between the coil  43  and the inner sleeve  42 . In the embodiment of  FIG. 13 , the torque braid  40  is disposed between the inner sleeve  42  and the vertebra  15 . In the embodiment of  FIG. 14 , the torque braid  40  is disposed between the vertebra  15  and the outer jacket  41 . In the embodiment of  FIG. 15 , the torque braid  40  is disposed within the coil  43 . 
         [0038]    The operation of the variably flexible insertion device  1  will now be described below by making reference to the above-described figures. The device  1  is flexed against the stiffness or spring constant k of the coil  43 , for example upon traversing the rectosigmoid junction, by sliding one or more of the knobs  6 . If it is desired to maintain that flexed condition for guiding an endoscope, such as a colonoscope, vacuum is applied at the connection or nipple  5  in the embodiment of  FIG. 6  or at the vacuum port  36  in the embodiment of  FIG. 8 . When suction is applied to create the vacuum, it causes the inner sleeve  42  and the outer jacket  41  to firmly contact each other with the tendons  11 ,  12  sandwiched and frictionally locked therebetween. Therefore, the vacuum connection or nipple  5  or the vacuum port  36  acts as a device for transitioning the hollow body  4 / 35 ,  7 ,  19 / 38 ,  41 ,  42 ,  43  between a relatively flexible condition and a relatively stiff condition through the application of a vacuum. As long as the vacuum is applied, the device  1  maintains its flexed condition. The positions of the knobs  6  in  FIGS. 1-3  show that in the flexed condition, the tendons  12  at the outer periphery of the bend become shorter and the tendons  12  at the inner periphery of the bend become longer, since they are all fixed in place at the first vertebra  13 . 
         [0039]    The tendons or wires are passive elements which are not in tension at any time. The tendons float within the hollow body when it is in the flexible condition, except where they are fixed to vertebra, such as at the distal end. The tendons are frictionally locked by the inner sleeve  42  and the outer jacket  41  when the hollow body is in the stiff condition. However, in both the relatively flexible condition and the relatively stiff condition, the tendons have no active control imposed on them and are not pulled or constrained. 
         [0040]    When it is desired to resume flexibility of the device  1 , the vacuum is vented or replaced by air at ambient or positive pressure. This causes the inner sleeve  42  and the outer jacket  41  to release the tendons and allows the stiffness or spring constant k of the coil  43  to place the device  1  into its normally flexible condition. 
         [0041]    The device is intended to be used in a manner similar to prior art devices. Therefore, the device will be placed over the endoscope. The endoscope will then be inserted into the rectum. The device will then be pushed in its flexible condition, to follow the curvature of the scope. The device will then be stiffened, allowing the scope to be pushed forward with less pressure exerted on the colon of the patient. This procedure can be repeated until the scope reaches the cecum. 
         [0042]    An alternative use of the device is to aid in small bowel endoscopy. The device is placed over the endoscope. The endoscope is inserted into the patient transorally, through the stomach and then partially into the small bowel. The device is then pushed in its flexible condition, to follow the curvature of the scope. The device is then stiffened, allowing the scope to be pushed forward without the scope looping in the stomach. 
         [0043]    Another use of the device is for aiding in access to internal body parts, such as the gallbladder, through an opening of an internal body cavity, such as the stomach. The device is placed over the endoscope. The endoscope is inserted into the patient transorally, through the stomach and then up against the internal surface of the stomach. The device is then pushed in its flexible condition, to follow the curvature of the scope. The device is then stiffened, allowing the surgeon to create an opening in the stomach wall without the scope looping in the stomach. Once the opening is created, the device and the scope can be advanced outside the stomach. The device can then be stiffened to create a stable platform to perform surgical procedures outside of the stomach. The device could contain one or more features (i.e. balloons) for sealing the outer periphery of the device to the stomach wall to prevent gastric fluids from exiting the stomach. 
         [0044]    In each of these procedures described above, the knobs and tendons are used to steer the insertion device within the body as needed, while the torque braid allows the device to be twisted as needed.