Abstract:
A torque-transmitting, variably-flexible, corrugated 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 corrugated tube transmits torque from the proximal end toward the distal end. A method for transmitting torque and variably flexing an insertion device for receiving an instrument includes providing a hollow body, transmitting torque along the hollow body with a corrugated tube, 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.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a divisional application of application Ser. No. 11/502,322, filed Aug. 10, 2006, of which priority is claimed under 35 USC §120; the prior application is herewith incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a torque-transmitting, variably-flexible, corrugated insertion device. The invention also relates to a method for transmitting torque and variably flexing a corrugated insertion device. 
     2. Description of the Related Art 
     Prior art insertion devices of this general type have been quite complicated, cumbersome and difficult to use. Such devices have a relatively large diameter, a limited maximum length, a limited transmission of torque and present obstacles to insertion of instruments. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a torque-transmitting, variably-flexible, corrugated insertion device and a method for transmitting torque and variably flexing a corrugated insertion device, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and which are simpler to construct, have a smaller diameter, a greater torque transmission, may be made longer and allow smooth insertion of an instrument. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a torque-transmitting, variably-flexible, corrugated insertion device which includes a hollow body having a proximal end with an entrance for receiving an instrument, such as a scope, 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 corrugated tube transmits torque from the proximal end toward the distal end. 
     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, such as a scope. The method includes providing a hollow body, transmitting torque along the hollow body with a corrugated tube, 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. 
     The corrugated tube supports the insertion device and maintains a tubular shape, without the need for a support spring. Therefore, the insertion device has a narrower diameter, may have a longer length, such as 50 inches or longer, transmits greater torque than a spring and does not impair the insertion of an instrument in contrast to a spring. 
     In accordance with another feature of the invention, there is provided an inner liner within the corrugated tube for preventing vacuum leakage and aiding in insertion of the instrument. The liner may be adhesively connected to the corrugated tube. 
     In accordance with a further feature of the invention, there are provided tendons within the hollow body for maintaining the hollow body in the relatively flexible and relatively stiff conditions. In a steerable embodiment of the device, some of the tendons are individually adjustable in length for steering the distal end of the hollow body. The tendons and the corrugated tube are at least partly disposed between an outer jacket and an inner sleeve where the transitioning device, such as a vacuum connection, applies suction for frictionally locking the tendons and the corrugated tube in place. 
     In accordance with an added feature of the invention, inner and outer handles of the hollow body define a vacuum plenum volume therebetween communicating between the outer jacket and the inner sleeve and with a vacuum port. A sliding valve encircles the outer handle and has a vacuum inlet/outlet for communicating with the vacuum connection. The sliding valve slides between a position in which the vacuum inlet/outlet communicates with the vacuum port and a position in which the vacuum inlet/outlet is sealed against the vacuum port. The sliding valve has a recessed O-ring for sealing the sliding valve to the outer handle. This provides a convenient way for the operator of the device to adjust the stiffness while manipulating the device. 
     In accordance with an additional feature of the invention, the tendons extend substantially entirely over a flexible section of the hollow body beyond the handle. The tendons float in the handle when the hollow body is in the relatively flexible condition. The tendons are not in tension or compression when the hollow body is in both the relatively flexible and relatively stiff conditions. The tendons are rigidly attached at the distal end and allowed to float at the handle. In this regard, there is provided a termination bushing at the distal end to which at least some of the tendons are attached. Each two of the tendons form legs of a U-shaped configuration passing through holes in the termination bushing and being interconnected by a crosspiece extending between two of the holes distally of the termination bushing, like a large staple. This avoids the need to weld the tendons in place at the distal end and removes the danger of welds breaking at the distal end. The tendons include steering tendons attached to the termination bushing and non-steering tendons attached to one of the vertebrae. 
     In accordance with yet another feature of the invention, the tendons vary in number along the hollow body for providing zones of varying stiffness. The number of tendons may be greater toward the distal end than toward the proximal end for increasing stiffness at the distal end. 
     In accordance with yet another feature of the invention, there are provided knobs each sliding in a respective slot formed in the handle. The individually adjustable tendons are each steering tendons connected to a respective one of the knobs for steering the distal end. This allows the operator of the device to easily steer the distal end in any direction. 
     In accordance with yet another feature of the invention, the corrugated tube has at least one cuffed end. The cuffed end or ends prevent vacuum leakage and thus preserve stiffness, when required. 
     In accordance with a concomitant feature of the invention, vertebrae are disposed along the corrugated tube for guiding the tendons. The vertebrae may be disposed between corrugation peaks of the corrugated tube and may be elastic and have a parting line to be opened into a gap for snapping the vertebrae onto the corrugated tube. At least some of the vertebrae have channels formed therein permitting movement of at least some of the tendons therethrough. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a torque-transmitting, variably-flexible, corrugated insertion device and a method for transmitting torque and variably flexing a corrugated 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. 
     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 SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a diagrammatic, side-elevational view of a torque-transmitting, variably-flexible, corrugated insertion device according to the invention, in which an outer jacket has been partly removed to show corrugations, tendons and vertebrae and in which the device has been steered to the right; 
         FIG. 2  is a side-elevational view of the insertion device in which corrugations are illustrated at the distal tip as in  FIG. 1  and in which an outer covering of a handle has been removed; 
         FIG. 3  is a perspective view showing stiffener zones of the insertion device and illustrating corrugations at the distal tip; 
         FIGS. 4 and 5  are fragmentary, side-elevational views of a steering assembly of the insertion device with corrugations illustrated in different locations; 
         FIG. 6  is an enlarged, fragmentary, longitudinal-sectional view of a distal tip region of the insertion device; 
         FIG. 7  is a view of the insertion device similar to  FIG. 6 , in which tendons have been shown; 
         FIG. 8  is an elevational view of a corrugated tube of the insertion device in which straight and stepped cuffs have been shown; 
         FIG. 9  is a fragmentary, longitudinal-sectional view of the insertion device in which an inner liner, an inner handle and a corrugation cuff have been shown; 
         FIG. 10  is a fragmentary, perspective view of the distal tip region of the insertion device; 
         FIG. 11  is a fragmentary, perspective view of the distal tip region of the insertion device in which the outer jacket has been removed to show the tendons, the vertebrae and the corrugations; 
         FIG. 12  is a view of the insertion device similar to  FIG. 11 , in which the tip has been removed; 
         FIG. 12A  is an enlarged, perspective view of a U-shaped tendon; 
         FIG. 13  is a view of the insertion device similar to  FIGS. 11 and 12 , in which the tip and a termination bushing have been removed; 
         FIG. 14  is a cross-sectional view of the insertion device, which is taken along a line IVX-IVX of  FIG. 11 , in the direction of the arrows; 
         FIG. 15  is a further enlarged, perspective view of a snap vertebra of the insertion device; and 
         FIG. 16  is a perspective view of a continuous vertebra of the insertion device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures of the drawings in detail and first, particularly, to  FIG. 1  thereof, there is seen a torque-transmitting, variably-flexible, corrugated 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 colonoscopy. 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 . An outer jacket  5  of the hollow body extends to a tip  7 , which may be formed of rubber, at the distal end  3 , but only a portion of the outer jacket has been shown in order to illustrate other details of the device disposed within the outer jacket  5 . A flexible strain relief retainer  6  is disposed between the handle  4  and the outer jacket  5 . The outer jacket  5  and the flexible strain relief retainer  6  provide a flexible section with a given length extending beyond the handle  4 . The handle  4  has a sliding valve  28  and a septum valve assembly  29 , which will be explained in greater detail below with regard to  FIG. 2 . The handle  4  also has a vacuum connection or nipple  35  for controlling stiffness of the device, as will be explained below as well. A corrugated tube  30 , which is only illustrated in the region of the distal tip  7 , actually extends to the flexible strain relief retainer  6 . 
     The insertion device  1  may be steerable or non-steerable. If the device is steerable, a steering assembly  10  is provided which includes six vertebrae  13 - 18  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  11 ,  11 ′ are equally spaced apart about the circumference of the hollow body between the vertebra  17  and the handle  4 , although only five can be seen in  FIG. 1 . Four of the tendons which extend from a tendon termination bushing  31  at the tip  7  to the handle  4  are so-called steering tendons  11 ′. Other tendons which only extend between the vertebra  17  and the handle  4  are so-called non-steering tendons  11 . 
     Each of the four steering tendons  11 ′ is attached at its proximal end to a respective knob  36  which slides within a respective slot  38  in the handle  4 . A stop  39  is also disposed on each tendon  11 ′. When a knob  36  is slid proximally, it pushes a stop  39  and pulls a tendon  11 ′ to steer the hollow body. In the condition shown in  FIG. 1 , the knob  36  at the bottom has been slid proximally so that the tip  7  of the hollow body has been steered downward. If different knobs  36  are moved, the hollow body will be steered in different directions. When the knobs  36  are forced distally, the knobs can freely slide independently of the tendons  11 ′ to prevent buckling of the tendons  11 ′. 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. 
     In  FIG. 2 , an outer covering of the handle  4  has been removed to show details of the sliding valve  28  and the septum valve assembly  29 . 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 . An O-ring seal is also disposed at the proximal end of the handle  4 . The grip  20  also has a vacuum inlet/outlet  23  for the connection or nipple  35 . When the grip  20  is slid toward an annular stop  26 , 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  35  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  35 . 
     The septum valve assembly  29  is in the form of an end cap which is inserted into the proximal end of the outer handle  18  and provides a so-called septum seal for insertion of an instrument  44 , such as an endoscopy or a colonoscopy, represented by a dot-dash line. 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 is provided between the septum valve assembly  29  and the inner handle  19 . 
     If the insertion device  1  is non-steerable, the number of tendons  11  may also be varied as shown in  FIG. 3  to provide stiffness zones. For example, a stiffness zone A closest to the distal tip  7  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. Vertebrae  12 - 18 , which in this case are seven in number, are also shown. The four tendons in the zone A all end at the termination bushing  31  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  14  between zones A and B, which is therefore referred to as a termination vertebra, 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 termination vertebra  16  between zones B and C but are free to slide elsewhere. 
       FIG. 4  shows the device  1  with the handle  4  removed, from which it can be seen that the four steering tendons  11 ′ of the steering assembly  10  continue toward the handle from the tip  7 , whereas the non-steering tendons  11  only run from the termination vertebra  15  to the handle. It is also seen that as the insertion device is steered, the steering tendons  11 ′ on the outside of the bend become shorter and the steering tendons  11 ′ on the inside of the bend become longer.  FIG. 5  shows a similar view to  FIG. 4 , in which it can be seen how a greater number of vertebrae react to bending. In the case of  FIG. 5 , eight steering tendons  11 ′ extend to the termination bushing  31 , whereas six non-steering tendons  11  extend from the termination vertebra  18  to the handle. 
     In the enlarged view of  FIG. 6 , a portion of the corrugated tube  30  in the region of the tip  7  and the termination bushing  31  are shown. The tendons  11 ,  11 ′, which have been omitted in  FIG. 6  for the sake of clarity, are shown in  FIG. 7  as extending through the vertebrae  13 ,  14  to the termination bushing  31 . A tip restrictor  32  can also be seen at the tip  7 . It may also be seen that an inner liner  33  extends within the corrugated tube  30 . One purpose of the inner liner is to provide a surface on which the instrument will pass smoothly within the corrugated tube. The corrugated tube  30  may be formed of nylon or another suitable material. The inner liner  33  is made from a sheet of white plastic material which has an adhesive coating on one side. The inner liner  33  is rolled around an inflatable mandrel and heated in an oven, to form a bonded seam  42  (shown in  FIGS. 11-13 ) and is sealed to an inner surface of the corrugated tube  30 . The corrugations of the corrugated tube  30  have peaks and valleys. As viewed from within the corrugated tube  30 , the inner liner  33  adheres to the peaks and extends somewhat into the valleys of the corrugations as dimples. Therefore, as the insertion device bends, the inner liner  33  stays tight along the corrugations on the outside of the bend and crinkles at the inside of the bend. The peaks and valleys of the corrugations also need not be of equal length along the length of the corrugated tube  30 . For example, 70% of the length may be peaks and 30% valleys or 80% of the length may be peaks and 20% valleys. These variations will add to the adhesion of the inner liner to the corrugated tube and reduce the formation of dimples. However, a 50/50 corrugation ratio is shown in the figures. The outer jacket  5  may be formed of polyurethane or another suitable material which is similarly a flat sheet that is rolled and seamed. The outer jacket  5  and the inner liner  33  both extend to the termination bushing  31 , which may be formed of polycarbonate. 
     The corrugated tube is cuffed in order to prevent leakage paths for the vacuum applied within the hollow body and to protect the material of the inner liner.  FIG. 8  illustrates two types of molded corrugation cuffs  34 , namely a straight cuff on the left and a stepped cuff on the right, of the figure, both with a 50/50 corrugation ratio.  FIG. 9  shows the inner handle  19  which is attached to a corrugation cuff  34 , as well as the inner liner  33  that is sealed to the corrugated tube  30  and to the inner handle  19  to prevent a vacuum leakage path. 
     The perspective view of  FIG. 10  illustrates the insertion device  1  in the region of the tip  7 , including the outer jacket  5  extending to the tip, which is not shown in the other figures. 
     The fragmentary, perspective view of  FIG. 11  illustrates the insertion device  1  in the region of the tip  7 , with the outer jacket removed to reveal the termination bushing  31  at the tip  7 , the corrugated tube  30 , the vertebrae  13 ,  14 , the tendons  11  or  11 ′ and the inner liner  33 . It is seen that the tendons slide through channels  37  in the vertebrae. 
     In  FIG. 12 , not only the outer jacket  5  but also the tip  7  have been removed to show how the tendons  11 ,  11 ′ are anchored in the termination bushing  31 . As can been seen, each tendon  11 ,  11 ′ passes through a respective hole  40  in the termination bushing  31 . Each two tendons together have a U-shape in the form of a large staple having a crosspiece  41  extending between two of the holes  40 . This avoids the necessity of welding ends of tendons to a terminating vertebra or ring. The U-shaped tendons and crosspiece are best seen in  FIG. 12A . 
     In  FIG. 13 , not only the outer jacket  5  and the tip  7  but also the termination bushing  31  have been removed to show a portion of the inner liner  33  which is sealed on the inner surface of the termination bushing  31  for vacuum sealing and smooth movement of the instrument or scope  44 . The crosspieces  41  of the tendons  11 ,  11 ′ as well as the seam  42  of the inner liner are also clearly shown. 
       FIG. 14  is a cross-sectional view of the insertion device  1  which is taken through the flexible tip restrictor  32 , as seen in the direction of the vertebra  13 . Therefore, the outer jacket  5 , the vertebra  13  with the tendons  11 .  11 ′, the corrugated tube  30  with the peaks and valleys and the tip restrictor  32 , can be seen. 
     Representative vertebrae  12 - 18  are shown in  FIGS. 15 and 16 . The vertebra of  FIG. 15  is a so-called latch ring constructed for snap installation. The vertebra is formed of elastic material which permits it to be expanded at a parting line and opened at a gap  43 , so that it can be snapped over the corrugated tube  30  between two peaks thereof. Therefore, the vertebra can be installed at any location desired along the corrugated tube for support of the tendons. The vertebra shown in  FIG. 16  is intended to be placed at an end of the corrugated tube  30 , where no expansion and snapping into place are required. 
     The operation of the variably flexible insertion device  1  will now be described below by making reference to the above-described figures. If the steerable embodiment is used, the device  1  is flexed against the stiffness of the corrugated tube  30 , for example upon traversing the rectosigmoid junction, by sliding one or more of the knobs  6 . In either the steerable or non-steerable embodiment, if it is desired to maintain that flexed condition for guiding an endoscope, such as a colonoscopy, vacuum is applied at the connection or nipple  35 . When suction is applied to create the vacuum, it causes the inner sleeve  33  and the outer jacket  5  to approach each other with the corrugated tube  30  and the tendons  11 ,  11 ′ sandwiched and frictionally locked therebetween. Therefore, the vacuum connection or nipple  35  acts as a device for transitioning the hollow body  4 ,  7 ,  19 ,  5 ,  33 ,  30  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 ,  2 ,  4  and  5  show that in the flexed condition, the tendons  11 ′ at the outer periphery of the bend become shorter and the tendons  11 ′ at the inner periphery of the bend become longer, since they are all fixed in place at the termination bushing  31 . 
     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 termination vertebrae or the termination bushing  31  at the distal end. The tendons are frictionally locked by the inner sleeve  33  and the outer jacket  5  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. 
     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  33  and the outer jacket  5  to release the tendons and allows the stiffness of the corrugated tube  30  to place the device  1  into its normally flexible condition. 
     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. 
     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. 
     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. 
     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 corrugated tube allows the device to be twisted as needed.