US20060009678A1 - Endoscope having a guide tube - Google Patents

Abstract

An endoscope having a guide tube is described herein. The assembly has an endoscope which is slidably insertable within the lumen of a guide tube. The guide tube is configured to be rigidizable along its entire length from a relaxed configuration. The endoscope has a steerable distal portion to facilitate the steering of the device through tortuous paths. In the relaxed configuration, a portion of the guide tube is able to assume the shape or curve defined by the controllable distal portion of the endoscope. Having assumed the shape or curve of the endoscope, the guide tube may be rigidized by the physician or surgeon to maintain that shape or curve while the endoscope is advanced distally through the tortuous path without having to place any undue pressure against the tissue walls.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This is a continuation of U.S. patent application Ser. No. 10/139,289 filed May 2, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 09/969,927 filed Oct. 2, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09/790,204 filed Feb. 20, 2001, which claims priority of U.S. Provisional Patent Application Ser. No. 60/194,140 filed Apr. 3, 2000, each of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
• The present invention relates generally to endoscopes and endoscopic medical procedures. More particularly, it relates to a method and apparatus to facilitate insertion of a flexible endoscope along a tortuous path using a guide tube apparatus, such as for colonoscopic examination and treatment.
BACKGROUND OF THE INVENTION
• An endoscope is a medical instrument for visualizing the interior of a patient's body. Endoscopes can be used for a variety of different diagnostic and interventional procedures, including colonoscopy, bronchoscopy, thoracoscopy, laparoscopy and video endoscopy.
• Colonoscopy is a medical procedure in which a flexible endoscope, or colonoscope, is inserted into a patient's colon for diagnostic examination and/or surgical treatment of the colon. A standard colonoscope is typically 135-185 cm in length and 12-19 mm in diameter, and includes a fiberoptic imaging bundle or a miniature camera located at the instrument's tip, illumination fibers, one or two instrument channels that may also be used for insufflation or irrigation, air and water channels, and vacuum channels.
• The colonoscope is inserted via the patient's anus and is advanced through the colon, allowing direct visual examination of the colon, the ileocecal valve and portions of the terminal ileum. Insertion of the colonoscope is complicated by the fact that the colon represents a tortuous and convoluted path. Considerable manipulation of the colonoscope is often necessary to advance the colonoscope through the colon, making the procedure more difficult and time consuming and adding to the potential for complications, such as intestinal perforation.
• Steerable colonoscopes have been devised to facilitate selection of the correct path though the curves of the colon. However, as the colonoscope is inserted farther and farther into the colon, it becomes more difficult to advance the colonoscope along the selected path. At each turn, the wall of the colon must maintain the curve in the colonoscope. The colonoscope rubs against the mucosal surface of the colon along the outside of each turn. Friction and slack in the colonoscope build up at each turn, making it more and more difficult to advance and withdraw the colonoscope. In addition, the force against the wall of the colon increases with the buildup of friction. In cases of extreme tortuosity, it may become impossible to advance the colonoscope all of the way through the colon.
• Steerable endoscopes, catheters and insertion devices for medical examination or treatment of internal body structures are described in the following U.S. patents, the disclosures of which are hereby incorporated by reference in their entirety: U.S. Pat. Nos. 4,543,090; 4,753,223; 5,337,732; 5,337,733; 5,383,852; 5,487,757 and 5,662,587.
BRIEF SUMMARY OF THE INVENTION
• An endoscopic assembly and method of advancing the assembly which is able to traverse tortuous paths, such as the colon, without excessively contacting the walls of the colon is described herein. The assembly generally comprises a combination of an endoscope which is slidably insertable within the lumen of a guide tube. The endoscope may be any conventional endoscope having a shaft which extends from a handle. The distal end of the shaft preferably comprises a controllable distal portion which may be manipulated to facilitate the steering of the assembly through the tortuous path. The guide tube may be a conventional flexible conduit which is configured to be rigidizable along its entire length from a relaxed configuration. In the relaxed configuration, a portion of the guide tube is able to assume the shape or curve defined by the controllable distal portion of the endoscope. Having assumed the shape or curve of the endoscope, the guide tube may be rigidized by the physician or surgeon to maintain that shape or curve.
• Alternatively, the guide tube may also be used with an endoscope having an automatically controlled proximal portion and a selectively steerable distal portion. Such a controllable endoscope may have a distal portion which is manually steerable by the physician or surgeon to assume a shape to traverse an arbitrary curved path and a proximal portion which is automatically controlled by, e.g., a computer, to transmit the assumed shape along the proximal portion as the endoscope is advanced or withdrawn. More detailed examples are described in copending U.S. patent application Ser. No. 09/969,927, which has been incorporated above by reference in its entirety.
• The guide tube may be comprised of a plurality of individual segments which are linked adjacent to one another via one or more tensioning wires or elements. These tensioning elements may be placed circumferentially about each of the segments and preferably run throughout the length of the guide tube through each of the individual segments. When the guide tube is to be rigidized, the tensioning elements may be pulled or tightened to draw the segments together such that the entire guide tube becomes rigid. The tensioning elements may then be loosened such that the individual segments may move relative to one another.
• In use, e.g., in the colon, the physician or surgeon may typically first advance the distal portion of the endoscope within the body of the patient. When the first curve of the colon is approached, the user may appropriately steer the distal portion of the endoscope to assume a curve for traversing the path. At this point, the endoscope is preferably held stationary relative to the patient while the guide, in a relaxed and flexible state, is advanced over the shaft of the endoscope until the distal end of the guide tube is at, or a short distance past, the distal tip of the endoscope. Once the guide tube, or at least its distal portion, has assumed the curve formed by the controllable distal portion of the endoscope, the guide tube may then be rigidized, preferably along its length, to hold its assumed shape. Once this is done, the endoscope may be further advanced within the rigidized guide tube to traverse the curved pathway without having to place any pressure against the walls of the colon. The steps for advancing the endoscope may be repeated as necessary until the desired area within the body has been reached.
• At any point during the exploratory procedure, the guide tube may be removed from the colon while leaving the endoscope behind. To remove the assembly from the colon, the guide tube may first be withdrawn and the endoscope may be subsequently withdrawn. Alternatively, the above steps may be repeated in reverse order to withdraw both the guide tube and the endoscope from the region.
• The outer surface of the guide tube preferably has a tubular covering which covers at least a majority of the tube to prevent the entry of debris and fluids within the lumen of the guide tube between the individual segments. The covering also facilitates the advancement and withdrawal of the guide tube by preventing tissue from being pinched between the segments. To prevent tissue from being pinched between the guide tube and endoscope during assembly movement, expandable bellows or an additional covering may optionally be placed over the distal opening of the guide tube. This additional covering may simply be an integral extension of the covering over the surface of the guide tube, or it may be a separate covering attached to the distal end of the guide tube. This covering may also be attached to or near the distal end of the endoscope to maintain a seal between the endoscope shaft and the guide tube. The coverings and their variations may be attached by any conventional method as practicable. If the covering over the distal end of the guide tube is utilized, as the distal portion of the endoscope shaft is advanced distally through the guide tube, the covering preferably expands distally along with the endoscope or simply slides distally along with the endoscope. When the shaft is retracted within the guide lumen, the covering again preferably retracts proximally along with the proximal movement of the distal end of the endoscope or it may simply be retracted manually along with the endoscope. The use of the additional covering may also aid in maintaining the sterility of the internal lumen of the guide tube.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows a variation of the guide tube assembly in which an endoscope is pushed through and supported by a guide tube.
• FIG. 2 shows a cross-sectional view of the guide tube assembly ofFIG. 1.
• FIG. 3 shows the guide tube variation ofFIG. 1 with a portion of the tube partially removed for clarity.
• FIG. 4 shows a variation on a steerable endoscope having a selectively steerable distal portion and an automatically controllable proximal portion which may be used with the rigidizable guide tube.
• FIG. 5 shows a wire frame model of a section of the automatically controllable endoscope traversing an arbitrary curve.
• FIG. 6A shows a variation in which the distal end of the endoscope remains unattached to the flexible covering.
• FIG. 6B shows another variation in which the distal end of the endoscope is attached to the flexible covering.
• FIG. 7 shows the distal end of the endoscope extending past the distal end of the guide tube and the flexible covering extending distally along with the endoscope.
• FIG. 8A shows another variation in which the covering is configured as an elastic tubular structure.
• FIG. 8B shows another variation in which the covering is configured as an elastic diaphragm structure.
• FIG. 9 shows the variations ofFIGS. 8A and 8B in which the endoscope is extended distally.
• FIG. 10 shows yet another variation in which a plastic covering is used to cover the endoscope and guide tube.
• FIGS. 11A to11E show a variation on advancing an endoscope through a colon using the guide tube as support.
• FIG. 12 shows a variation in which the guide tube may be withdrawn from the colon while leaving the endoscope behind.
DETAILED DESCRIPTION OF THE INVENTION
• As shown inFIG. 1, a representative illustration of a variation onguide tube assembly10 is seen partially disassembled for clarity.Assembly10 generally comprises anendoscope12 which is insertable withinguide tube14 throughguide lumen16.Endoscope12 may be any conventional type endoscope having ahandle18 withshaft20 extending therefrom. The distal end ofshaft20 preferably comprises a controllabledistal portion22 which may be manipulated to facilitate the steering of the device through the body.Endoscope shaft20 may be slidingly disposed withinguide lumen16 such that controllabledistal portion22 is able to be passed entirely throughguide tube14 and outdistal opening24 defined at the distal end oftube14.
• Alternatively, guidetube14 may also be used with an endoscope having an automatically controlled proximal portion and a selectively steerable distal portion, as described in further detail below. Such a controllable endoscope may have a distal portion which is manually steerable by the physician or surgeon to assume a shape to traverse an arbitrary curved path and a proximal portion which is automatically controlled by, e.g., a computer, to transmit the assumed shape along the proximal portion as the endoscope is advanced or withdrawn. More detailed examples are described in copending U.S. patent application Ser. No. 09/969,927, which has been incorporated above by reference in its entirety.
• One example of such an endoscope is shown inFIG. 4, which shows one variation of steerable endoscope80. Endoscope80 has anelongate body82 with a manually or selectively steerabledistal portion84 and an automatically controlledproximal portion86. The selectively steerabledistal portion84 can be selectively steered or bent up to a full 180° bend in any direction. A fiberoptic imaging bundle92 and one or more illumination fibers94 may extend throughbody82 fromproximal end90 todistal end88. Alternatively, endoscope80 may be configured as a video endoscope with a miniaturized video camera, e.g., a CCD camera, positioned atdistal end88 ofendoscope body82. The images from the video camera may be transmitted to a video monitor by a transmission cable or by wireless transmission where images may be viewed in real-time or recorded by a recording device onto analog recording medium, e.g., magnetic tape, or digital recording medium, e.g., compact disc, digital tape, etc. Optionally,body82 of endoscope80 may include one or two, instrument channels96,98 that may also be used for insufflation or irrigation, air and water channels, vacuum channels, etc.Body82 of endoscope80 is preferably highly flexible so that it is able to bend around small diameter curves without buckling or kinking while maintaining the various channels intact. When configured for use as a colonoscope,body82 of the endoscope80 may range typically from 135 to 185 cm in length and approximately 12-13 mm in diameter. Endoscope80 can be made in a variety of other sizes and configurations for other medical and industrial applications.
• Aproximal handle100 is attached toproximal end90 ofelongate body82. Handle100 may include ocular104 connected to fiberoptic imaging bundle92 for direct viewing and/or for connection to avideo camera106 or a recording device108. Handle100 may be connected to an illumination source110 by illumination cable116 that is connected to or continuous with illumination fibers94. A first luer lock fitting112 and a second luer lock fitting114 on thehandle100 may be connected to instrument channels96,98.
• Handle100 may be connected to anelectronic motion controller122 by way ofcontroller cable118.Steering control102 may be connected toelectronic motion controller122 by way of asecond cable120.Steering control102 may allow the user to selectively steer or bend selectively steerabledistal portion84 ofbody82 in the desired direction.Steering control102 may be a joystick controller as shown, or other known steering control mechanism.Electronic motion controller122 may control the motion of automatically controlledproximal portion86 ofbody82. Theelectronic motion controller122 may be implemented using a motion control program running on a microcomputer or using an application-specific motion controller. Alternatively,electronic motion controller122 may be implemented using, a neural network controller.
• Anaxial motion transducer124 may be provided to measure the axial motion of theendoscope body82 as it is advanced and withdrawn. Theaxial motion transducer124 can be made in many possible configurations. By way of example, theaxial motion transducer124 inFIG. 4 is configured as aring126 that may entirely or partially surroundbody82 of endoscope80. Theaxial motion transducer124 is preferably attached to a fixed point of reference, such as the surgical table or the insertion point for endoscope80 on the patient's body. Asbody82 of endoscope80 slides throughaxial motion transducer124, it produces a signal indicative of the axial position ofendoscope body82 with respect to the fixed point of reference and sends a signal toelectronic motion controller122 by telemetry or by a cable (not shown).Axial motion transducer124 may use optical, electronic or mechanical methods to measure the axial position ofendoscope body82. Other possible configurations for theaxial motion transducer124 are further described in copending U.S. patent application Ser. No. 09/969,927.
• FIG. 5 shows a wire frame model of a section ofbody82 of endoscope80 in a neutral or straight position. Most of the internal structure ofendoscope body82 has been eliminated in this drawing for the sake of clarity.Endoscope body82 is divided up into segments orsections 1, 2, 3, . . . , etc. The geometry of each segment is defined by four length measurements along the a, b, c and d axes and each of the adjacent segments are preferably interconnected via joints which allow the independent angular movement and/or rotation of each segment relative to one another. For example, the geometry ofsegment 1 is defined by the four length measurements l_1a, l_1b, l_1c, l_1d, and the geometry ofsegment 2 is defined by the four length measurements l_2a, l_2b, l_2c, l_2d, etc. Eachadjacent segment 1, 2, 3, etc., are preferably individually controlled by linear actuators (not shown), e.g., electric, pneumatic, hydraulic, etc. motors. The linear actuators may utilize one of several different operating principles. For example, to bend theendoscope body82 in the direction of the a axis, the measurements l_1a, l_2a, l_3a. . . l_10acan be shortened and the measurements l_1b, l_2b, l_3b. . . l_10bwould be lengthened an equal amount. The amount by which these measurements are changed determines the radius of the resultant curve. Alternatively, individual motors may be actuated to move adjacent segments relative to one another to effect a resultant curvature, as described in further detail in U.S. patent application Ser. No. 09/969,927.
• In the automatically controlledproximal portion86, each segment may be automatically controlled byelectronic motion controller122, which uses a curve propagation method to control the shape ofendoscope body82.Endoscope body82 has been maneuvered through the curve in colon C with the benefit of selectively steerabledistal portion84 and now automatically controlledproximal portion86 resides in the curve. When endoscopebody82 is advanced distally by one unit,segment 1 moves into the position marked1′,segment 2 moves into the position previously occupied bysegment 1, segment 3 moves into the position previously occupied bysegment 2, etc. Theaxial motion transducer124 produces a signal indicative of the axial position ofendoscope body82 with respect to a fixed point of reference and sends the signal to theelectronic motion controller122, under control of theelectronic motion controller122, eachtime endoscope body82 advances one unit, each segment in automatically controlledproximal portion86 is signaled to assume the shape of the segment that previously occupied the space that it is now in. Thus, the curve propagates proximally along the length of automatically controlledproximal portion86 ofendoscope body82. The curve appears to be fixed in space, asendoscope body82 advances distally.
• Similarly, when theendoscope body82 is withdrawn proximally, eachtime endoscope body82 is moved proximally by one unit, each segment in automatically controlledproximal portion86 is signaled to assume the shape of the segment that previously occupied the space that it is now in. The curve propagates distally along the length of the automatically controlledproximal portion86 ofendoscope body82, and the curve appears to be fixed in space, asendoscope body82 withdraws proximally. Wheneverendoscope body82 is advanced or withdrawn,axial motion transducer124 preferably detects the change in position andelectronic motion controller122 propagates the selected curves proximally or distally along automatically controlledproximal portion86 ofendoscope body82 to maintain the curves in a spatially fixed position. This allowsendoscope body82 to move through tortuous curves without putting unnecessary force on the walls of colon C.
• One example of usingassembly10, e.g., in the colon, the physician or surgeon may typically first advancedistal portion22 ofendoscope12 within the body of the patient. Upon reaching the first point at whichendoscope12 requires steering to negotiate a curved pathway, the user may appropriately steerdistal portion22 to assume a curve for traversing the pathway. At this point withendoscope12 held stationary relative to the patient, guidetube14 may be advanced overshaft20 until the distal end ofguide tube14 is at, a short distance before, or a short distance past, the distal tip of controllabledistal portion22. The short distance is considered to range anywhere from a few centimeters to several inches. Whileguide tube14 is advanced overshaft20,tube14 is preferably in a non-rigid state and is flexible enough to assume the curve formed by controllabledistal portion22.
• Oncetube14, or at least its distal portion, has assumed the curve formed by controllabledistal portion22,tube14 is rigidized preferably along its length to hold its assumed shape. Once this is accomplished,shaft20 ofendoscope12 may be further advanced within therigidized guide tube14 to traverse the curved pathway without having to place any pressure against the walls of the colon.
• Alternatively, if automatically controllable endoscope80 is utilized, it may generally be used in the same manner asconventional endoscope12. However, becauseendoscope body82 is automatically controllable either along its entire length or along several segments proximally of steerabledistal portion84, the steerabledistal portion84 may be advanced farther past the distal end ofguide tube14 than might be possible withconventional endoscope12. Controllable endoscope80 may be used in all other aspects similarly asconventional endoscope12 as described herein.
• Returning toFIG. 1, bellows or covering26 may coverdistal opening24 ofguide tube14 to prevent the entry of debris and fluids withinguide lumen16. Asdistal portion22 ofshaft20 is advanced distally throughtube14 and out ofguide lumen16, covering26 is preferably configured to expand distally either over or withshaft20 while maintaining a seal withguide lumen16. Whenshaft20 is retracted withinguide lumen16 or whenguide tube14 is advanced distally relative toshaft20, covering26 is preferably configured to retract proximally back overdistal opening24 along with the proximal movement ofdistal portion22. The use of covering26 is optional and may be used to maintain the sterility ofguide lumen16. Covering26 may also be used to prevent the pinching and tearing of tissue whenshaft20 is withdrawn withinguide lumen16.
• Guide tube14 may be any conventional appropriately flexible conduit which is capable of being rigidized along its entire length. The variation shown inFIG. 1 is comprised of a plurality ofindividual segments28 which are linked adjacent to one another via several, i.e., more than one, tensioning wires orelements30.Segments28 may be a series of interconnecting ball-and-socket type segments which allowadjacent segments28 to angularly pivot relative to one another to form an angle for traversing curves. Thesesegments28 may be rigidized via tensioningelements30 which may be placed circumferentially aboutsegments28, as shown inFIG. 2, which is a cross-sectioned view ofassembly10 fromFIG. 1. In this variation, there are four tensioningwires30A,30B,30C,30D which are each placed 90° relative to one another. Although four wires are shown in this example, a fewer number of wires may also be used, e.g., three wires. Each of thesewires30A,30B,30C,30D may be routed through an integral channel or lumen defined in the walls of eachsegment28. Moreover, they may be individually manipulated or they may all be manipulated simultaneously to effect a tensioning force for either rigidizing or relaxingguide tube14 along its length.
• FIG. 2 also shows the relative positioning ofshaft20 in relation tosegment28. As seen,shaft20, which may contain any number ofchannels34 for illumination fibers, optical fibers, etc., and workingchannels34, is slidingly disposed withinguide lumen16. This variation shows a gap separation between the outer surface ofshaft20 and the inner surface ofsegment28. This gap may vary depending upon the diameter of the endoscope being used and the desired cross-sectional area ofguide tube14, but a nominal separation is preferable to allow the uninhibited traversal ofshaft20 withinguide lumen16. An example of a rigidizable conduit structure which may be utilized as part of the present invention is shown and described in further detail in U.S. Pat. No. 5,251,611 to Zehel et al., which is incorporated herein by reference in its entirety.
• The outer surface ofguide tube14 preferably has a tubular covering32 which covers at least a majority oftube14. Tubular covering32 may provide a barrier between the debris and fluids of the body environment and theinterior guide lumen16, if also used with covering26. Moreover, covering26 may be an integral extension of tubular covering32 and may accordingly be made from a continuous layer of material. Tubular covering32 may also provide a lubricous cover to facilitate the insertion and movement ofguide tube14 along the walls of the body lumen as well as to provide a smooth surface inbetween theindividual segments28 to prevent the tissue from being pinched or trapped. Tubular covering32 may be made from a variety of polymeric materials, e.g., PTFE, FEP, Tecoflex, etc.
• FIG. 3 shows a side view ofguide tube variation14 with a portion of the wall partially removed for clarity. As shown,individual segments28 are aligned adjacent to one another with interconnectingsleeves40 placed inbetween.Sleeves40, in this variation, may be used to provide a pivoting structure to allowguide tube14 to flex into different positions. Alternatively,segments28 may be curved ball-and-socket type joints configured to interfit with one another. Tubular covering32 may also be seen to cover at least the majority ofguide tube14. Optionally, a distal end portion ofguide tube14 may be configured to be controllable such thatguide tube14, like the controllabledistal portion22 of theendoscope12, may define an optimal path for traversal.
• Bellows or covering26 may optionally be appended to the distal end ofconventional endoscope shaft20 orcontrollable shaft82. Throughout the description herein, automaticallycontrollable endoscope82 may be interchanged withconventional endoscope12 when used inguide tube14 as well as with the use of bellows or covering26. Although descriptions on the method of use may describe use withconventional endoscope12, this is done for brevity and is not intended to be limiting. The description is intended to apply equally to use with controllable endoscope80 since the two may be easily interchanged depending upon the desired use and result.FIG. 6A shows one variation in whichshaft20 or80 is unattached to covering26 such thatendoscope12 may be freely inserted and withdrawn fromguide lumen16. Covering26 may be omitted altogether from the assembly but is preferably used not only to help maintain anunobstructed guide lumen16, but also to prevent the walls of the body lumen from being pinched between theendoscope shaft20 or80 and guidetube14 during advancement of the assembly. As seen inFIG. 6A, covering26 may be separately attached atattachment region50 to the outer surface or distal edge ofguide tube14. Covering26 may also further comprise agusseted region52 which allows the covering26 to be compressed into a small compact profile and expanded much like a bellows duringshaft20 or80 advancement. Whenshaft20 or80 is withdrawn,gusseted region52 may allow covering26 to recompress or reconfigure itself back into its compacted shape. In this variation, covering26 is unattached toshaft20 or80; therefore, once the assembly has reached a predetermined location within the colon, covering26 may be removed through a working channel withinendoscope12 or the working tools may simply be pierced through covering26, although this is less preferable, before a procedure may be begin.
• FIG. 6B shows another variation where covering26 may be attached to theendoscope shaft20 or80 near or at the distal end of controllabledistal portion22 alongattachment region54. Asshaft20 or80 is advanced or withdrawn fromguide lumen16, covering26 remains attached to theendoscope12.FIG. 7 showsshaft20 or80 being advanced to a distal position throughguide lumen16. Asshaft20 or80 is advanced,gusseted region52 may be seen expanding to accommodate the distal movement. Thegusseted region52 may be configured to allowshaft20 or80 to be advanced to any practical distance beyondguide tube14, e.g., a few or several inches, depending upon the application. With this variation,shaft20 or80 may be extended throughguide lumen16 to this distal position prior to first advancingshaft20 or80 within the colon of a patient as well as to allow enough room so that the controllabledistal portion22 may have enough space to be manipulated to assume a desired shape or curve over which guidetube14 may be advanced over.
• Another variation is shown inFIG. 8A in which covering60 may be configured as an elastic tubular member. As seen, when endoscopeshaft20 or80 is in a retracted position, covering60 may be configured to form a tubular structure when relaxed. Asendoscope shaft20 or80 is advanced distally, as seen inFIG. 9, covering60 may stretch along withshaft20 or80 to maintain the sterility ofguide lumen16.
• Yet another variation is shown inFIG. 8B in which covering62 may be configured as an elastic rolling diaphragm. When endoscopeshaft20 or80 is retracted, covering62 may be configured to evert upon itself such that part of covering62 may be pulled proximally intoguide lumen16. Such a covering62 material may comprise any number of elastomers, elastomeric materials, or rubber-type materials, e.g., neoprene or latex. When endoscopeshaft20 or80 is advanced distally, covering62 may likewise revert and stretch distally along withshaft20 or80, also as shown inFIG. 9.
• Alternatively, the covering may simply be a plastic covering orwrapper64 which is non-elastic, as shown inFIG. 10.Such coverings64 are conventionally available and may be advanced along withendoscope shaft20 or80 and retracted likewise asendoscope shaft20 or80 is retracted.
• FIGS. 11A to11E show one variation of advancing aconventional endoscope12 using theguide tube14.FIG. 11A shows an illustrative colon C of a patient.Endoscope12 may be inserted within colon C through the anus A of the patient. As thedistal portion22 is advanced through rectum R, it encounters its first point of curvature. Here, controllabledistal portion22 may be manipulated much as a conventional endoscope to select an optimal path into sigmoid colon S. The optimal path is one which presents the most efficient path for advancingendoscope12 with the least amount of contact against the walls of colon C.
• Oncedistal portion22 has been manipulated to select the appropriate shape, guidetube14 may be advanced through anus A and rectum R overendoscope12 whileendoscope12 is maintained stationary relative to colonC. Guide tube14 is preferably in a relaxed state and is able to conform easily to the shape defined by controllabledistal portion22.Guide tube14 may be advanced to the distal end ofdistal portion22, a short distance before, or a short distance past the distal end ofportion22, as shown in.FIG. 11B. Onceguide tube14 has been advanced distally, it may be rigidized along its length such that it maintains the shape defined byendoscope12.
• Then, withguide tube14 rigidized, it is preferably held stationary relative to colon C whileendoscope12 is further advanced throughguide tube14 untildistal portion22 reaches the next point of curvature. Controllabledistal portion22 may then be manipulated to select an optimal path into descending colon D, as shown inFIG. 11C. Once the optimal path has been selected,endoscope12 is preferably maintained stationary relative to colon C whileguide tube14 is placed into its relaxed state and advanced overendoscope12.Guide tube14 may be advanced distally until the distal end ofendoscope12 is reached, as shown inFIG. 11D. At this point, guidetube14, having assumed the shape defined by controllabledistal portion22, may be rigidized along its length to maintain this shape.Endoscope12 may then be advanced distally again, as seen inFIG. 11E, while using therigidized guide tube14 to provide the column strength to advanceendoscope12 without the need to unnecessarily contact the walls ofcolon C. Endoscope12 may be advanced untildistal portion22 reaches the flexure between descending colon D and transverse colon T. Once this point is reached, the steps described above may be repeated as necessary untilendoscope12 has negotiated its way through transverse colon T, and ascending colon G until cecum E has been reached, or until a desired location within colon C has been reached.
• At any point during the exploratory procedure, guidetube14 may be removed from colon C while leavingendoscope12 behind, as shown inFIG. 12 by tube withdrawal70. Ifendoscope12 were left within colon C, theendoscope12 may be used and manipulated as any conventional endoscope or colonoscope would be during a conventional colonoscopy examination.Guide tube14 may also be partially retracted to allow thedistal portion22 to be steered or manipulated to examine or treat the colon C while still providing support and guidance to the proximal scope section ofendoscope12. To remove the assembly from colon C, guidetube14 may first be withdrawn, as shown, andendoscope12 may be subsequently withdrawn. Alternatively, the above steps may be repeated in reverse order to withdraw both guidetube14 andendoscope12 from colon C.
• The applications of the guide tube system and methods of use discussed above are not limited to regions of the body but may include any number of further treatment applications. Other treatment sites may include areas or regions of the body around organ bodies. Additionally, the present invention may be used in other environments which present tortuous paths such as exploratory procedures on piping systems, ducts, etc. Moreover, various other rigidizable guide tube apparatus and applications may be utilized beyond what is described herein. Modification of the above-described assemblies and methods for carrying out the invention, and variations of aspects of the invention that are obvious to those of skill in the art are intended to be within the scope of the claims.

Claims (7)

1-19. (canceled)

20. A method for advancing a first diagnostic or therapeutic instrument having a steerable distal tip into a natural or artificial opening in the body, the method comprising:

providing access into a natural or artificial opening in the body using an overtube comprising an elongated portion having a distal opening, a lumen extending therethrough to permit passage of the first diagnostic or therapeutic instrument, and a flexible distal region, and an atraumatic tip disposed on the flexible distal region;

inserting the first diagnostic or therapeutic instrument through the lumen so that the steerable distal tip is aligned with the flexible distal region; and

navigating the first diagnostic or therapeutic instrument together with the overtube through the portion of the body accessed by the natural or the artificial opening by steering the steerable distal tip of the first diagnostic or therapeutic instrument, thereby deflecting the flexible distal region of the overtube.

21. The method ofclaim 20 further comprising:

locking the overtube in a bent configuration; and

advancing the first diagnostic or therapeutic instrument through the lumen of the overtube in the bent configuration.

22. The method ofclaim 21 wherein the overtube comprises a plurality of nestable elements, and a tensioning mechanism that selectively applies a clamping load to the plurality of nestable elements, and locking the overtube in a bent configuration comprises actuating the tensioning mechanism.

23. The method ofclaim 21 wherein the overtube comprises a plurality of links, each link having a bore that defines the lumen of the overtube, and locking the overtube in a bent configuration comprises applying a clamping load to the plurality of links.

24. The method ofclaim 20 further comprising deflecting a portion of the body accessed through the natural or the artificial opening with the atraumatic tip so that tissue is not caught or pinched when the first diagnostic or therapeutic instrument is translated through the distal opening.

25. The method ofclaim 20, wherein a second diagnostic or therapeutic instrument is disposed adjacent the first diagnostic or therapeutic instrument, the method further comprising:

advancing the second diagnostic or therapeutic instrument alongside the first diagnostic or therapeutic instrument in an overtube dimensioned to permit passage of a second diagnostic or therapeutic instrument alongside the first diagnostic or therapeutic instrument.

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