US20060089528A1 - Method of navigating a therapeutic instrument with an apparatus having a handle coupled to an overtube - Google Patents

Abstract

An endoscope with guiding apparatus is described herein. A steerable endoscope is described having an elongate body with a manually or selectively steerable distal portion, an automatically controlled portion, a flexible and passively manipulated proximal portion, and an externally controlled and manipulatable tracking rod or guide. The tracking rod or guide is positioned within a guide channel within the endoscope and slides relative to the endoscope. When the guide is in a flexible state, it can conform to a curve or path defined by the steerable distal portion and the automatically controlled portion. The guide can then be selectively rigidized to assume that curve or path. Once set, the endoscope can be advanced over the rigidized guide in a monorail or “piggy-back” fashion so that the flexible proximal portion follows the curve held by the guide until the endoscope reaches a next point of curvature within a body lumen.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation-in-part of U.S. patent application Ser. No. 10/087,100 entitled “Endoscope with Guiding Apparatus” filed Mar. 1, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 09/969,927 entitled “Steerable Segmented Endoscope and Method of Insertion” filed Oct. 2, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09/790,204 entitled “Steerable Endoscope and Improved Method of Insertion” filed Feb. 20, 2001, which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/194,140 entitled the same and filed Apr. 3, 2000, all of which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
• The present invention relates generally to endoscopes and endoscopic procedures. More particularly, it relates to a method and apparatus to facilitate insertion of a flexible endoscope along a tortuous path, 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, withdraw, and loop 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; 5,624,381; 5,662,587; and 5,759,151.
SUMMARY OF THE INVENTION
• Accordingly, an improved endoscopic apparatus is disclosed herein for the examination of a patient's colon, other internal bodily cavities, and any other spaces within the body with minimal impingement upon bodily cavities or upon the walls of the organs. The disclosed apparatus may also be employed for various surgical treatments of those regions, e.g., insufflation, drug delivery, biopsies, etc. A steerable endoscope having an elongate body with a manually or selectively steerable distal portion, an automatically controlled portion, which may be optionally omitted from the device, a flexible and passively manipulated proximal portion, and an externally controlled and manipulatable tracking rod or guide is described below. The tracking rod or guide may be slidably positioned within a guide channel or lumen within the endoscope or it may be externally positionable such that the guide and the endoscope may slide relative to one another along a rail or channel located along an external surface of the endoscope.
• In operation, the steerable distal portion of the endoscope may be first advanced into a patient's rectum via the anus. The endoscope may be simply advanced, either manually or automatically by a motor, until the first curvature is reached. At this point, the steerable distal portion may be actively controlled by the physician or surgeon to attain an optimal curvature or shape for advancement of the endoscope. The optimal curvature or shape is considered to be the path which presents the least amount of contact or interference from the walls of the colon. In one variation, once the desired curvature has been determined, the endoscope may be advanced further into the colon such that the automatically controlled segments of controllable portion follow the distal portion while transmitting the optimal curvature or shape proximally down the remaining segments of the controllable portion. The operation of the controllable segments will be described in further detail below.
• In one variation, the guide is shorter than the full length of the endoscope, e.g., approximately the length of the controllable portion, and this shortened guide can be preloaded through the proximal end of the endoscope or through the handle of the endoscope. Once the guide is inserted, it may be advanced distally through the endoscope to the distal tip of the endoscope. As the user advances the endoscope distally, the automatically controlled segments of the proximal controllable portion propagate the selected curves down the endoscope, and the guide, in its flexible state, passively conforms to the shape of the desired pathway. Once the endoscope has advanced to a desired position, e.g. to a depth less than the length of the controllable portion of the endoscope, the user can rigidize the guide and maintain it at that depth (or axial position). The endoscope can then be further advanced relative to the rigidized guide, sliding over the rigid guide and along the selected pathway. Thus, the surgeon or physician only needs to lock the guide in position once. If the controllable region of the endoscope and the guide are each at least half of the length of the endoscope, the entire endoscope can conform to a selected pathway in this manner. It is also possible to reposition the guide easily by relaxing and/or unlocking it from its rigidized axial position and then moving the guide into its new position.
• In an alternative variation, once the steerable distal portion has been steered or positioned for advancement, the guide may be advanced distally in its flexible state along or within the endoscope until it reaches a distal position, i.e., preferably some point distal of the flexible proximal portion. Regardless whether the optional controllable portion is omitted or not from the device, the guide may be advanced near or to the end of the distal portion. Once the guide has been advanced, it may directly attain and conform to the curvature or shape defined by the steerable distal portion.
• Preferably, the guide is advanced to the distal end of steerable distal portion or, if the controllable portion is included in the device, the guide may be advanced to the distal end of the controllable portion, or to some point between the two portions. The guide may be advanced to any distal position as long as a portion of guide attains and conforms to the optimal curvature or shape. Prior to advancing the endoscope over the guide, the guide may be left in its flexible state or it may be optionally rigidized, as discussed further below. If left in its flexible state, the guide may possibly provide desirable column strength to the endoscope as it is advanced through the colon over the guide. It is preferable, however, that the guide is rigidized once it has attained and conformed to the curvature. This allows the flexible proximal portion, i.e., the passive portion, to remain flexible and lightweight in structure. As the position of the guide is preferably rigidized and maintained, the endoscope may then be advanced over the guide in a monorail or “piggy-back” fashion so that the flexible proximal portion follows the curve held by the guide until the endoscope reaches the next point of curvature.
• In some variations, the process of alternately advancing the guide and the endoscope may be repeated to advance the entire endoscope through the colon while the guide may be alternatively rigidized and relaxed while being advanced distally. While the endoscope is advanced through the colon, the physician or surgeon may stop the advancement to examine various areas along the colon wall using, e.g., an imaging bundle located at the distal end of the endoscope. During such examinations, the guide may be temporarily withdrawn from the endoscope to allow for the insertion of other tools through the guide channel if there is no separate channel defined within the endoscope for the guide. The guide may also be withdrawn through the instrument to any location within the body of the endoscope. In other words, the guide may be withdrawn partially or removed entirely from the endoscope at any time, if desired, because there are no constraints which may limit the travel of the guide through the body of the endoscope. After a procedure has been completed on the colon wall, the tool may be withdrawn from the guide channel and the guide may be reintroduced into the endoscope so that the endoscope may optionally be advanced once again into the colon.
• A further variation on advancing the endoscope may use multiple guides which are alternately rigidized while being advanced distally along a path. Although multiple guides may be used, two guides are preferably utilized. As the endoscopic device approaches a curvature, a first guide may be advanced in a relaxed and flexible state towards the steerable distal end of the device. While being advanced, the first guide preferably conforms to the shape defined by the distal end and the first guide may be subsequently rigidized to maintain this shape. The device may then be advanced further distally along the pathway while riding over the rigidized first guide.
• After the device has been advanced to its new position, a second guide may also be advanced distally in its relaxed state through the device up to the distal end while the first guide is maintained in its rigidized state. The second guide may then conform to the new shape defined by the distal end of the device and become rigidized to maintain this new shape. At this point, the first guide is also preferably maintained in its rigid state until the distal end of the device has been advanced further distally. The first guide may then be relaxed and advanced while the rigidity of the second guide provides the strength for advancing the guide. This procedure may be repeated as necessary for negotiating the pathway.
• To withdraw the endoscope from within the colon, the procedure above may be reversed such that the withdrawal minimally contacts the walls of the colon. Alternatively, the guide may simply be removed from the endoscope while leaving the endoscope within the colon. Alternatively, the guide may be left inside the endoscope in the relaxed mode. The endoscope may then be simply withdrawn by pulling the proximal portion to remove the device. This method may rub or contact the endoscope upon the walls of the colon, but any impingement would be minimal.
• The selectively steerable distal portion can be selectively steered or bent up to a full 180° bend in any direction. A fiberoptic imaging bundle and one or more illumination fibers may extend through the body from the proximal portion to the distal portion. The illumination fibers are preferably in communication with a light source, i.e., conventional light sources, which may be positioned at some external location, or other sources such as LEDs. Alternatively, the endoscope may be configured as a video endoscope with a miniaturized video camera, such as a CCD camera, positioned at the distal portion of the endoscope body. The video camera may be used in combination with the illumination fibers. Optionally, the body of the endoscope may also include one or two access lumens that may optionally be used for insufflation or irrigation, air and water channels, and vacuum channels, etc. Generally, the body of the endoscope is highly flexible so that it is able to bend around small diameter curves without buckling or kinking while maintaining the various channels intact. The endoscope can be made in a variety of other sizes and configurations for other medical and industrial applications.
• In some variations the endoscope may optionally include a suction device that can withdraw air or other gases, e.g. gases used for insufflating the interior of a colon. In the example of insufflating a colon, the insufflated gas may be trapped within regions of the colon due to the sacculation and movement of the colon walls. To facilitate removal of these gases, the suction device may be utilized to withdraw these trapped gases as the endoscope is advanced or withdrawn through the colon.
• The suction device may comprise a suction tube positioned within the endoscope and connected to a suction port defined along the endoscope outer surface at a location proximal of the distal tip. The suction port can apply suction at some distance from the tip of the endoscope so that the suction does not interfere with insufflation or other activities at the distal end of the endoscope. In one variation, the suction port is located in the distal half of the endoscope, approximately one-quarter down the length of the insertable portion of the endoscope, e.g., 40 to 50 cm from the steerable tip. Some variations may apply suction continuously, while others allow the user to selectively control application of the suction.
• The optional controllable portion is composed of at least one segment and preferably several segments which may be controllable via a computer and/or controller located at a distance from the endoscope. In one variation, approximately half of the length of the endoscope is comprised of controllable segments. Each of the segments preferably have an actuator mechanically connecting adjacent segments to allow for the controlled motion of the segments in space. The actuators driving the segments may include a variety of different types of mechanisms, e.g., pneumatic, vacuum, hydraulic, electromechanical motors, drive shafts, etc. If a mechanism such as a flexible drive shaft were utilized, the power for actuating the segments would preferably be developed by a generator located at a distance from the segments, i.e., outside of a patient during use, and in electrical and mechanical communication with the drive shaft. Alternatively, segments could be actuated by push-pull wires or tendons, e.g. Bowden cables, that bend segments by distributing force across a segment, as described in “Tendon-Driven Endoscope and Methods of Insertion” filed Aug. 27, 2002 (attorney docket number 514812000125), which is incorporated in its entirety by reference.
• A proximal portion comprises the rest of the endoscope and preferably a majority of the overall length of the device. The proximal portion is preferably a flexible tubing member that may conform to an infinite variety of shapes. It may also be covered by a polymeric covering optionally extendable over the controllable portion and the steerable distal portion as well to provide a smooth transition between the controllable segments and the flexible tubing of the proximal portion. The controllable portion may be optionally omitted from the endoscope. A more detailed description on the construction and operation of the segments may be found in U.S. patent application Ser. No. 09/969,927 entitled “Steerable Segmented Endoscope and Method of Insertion” filed Oct. 2, 2001, which has been incorporated by reference in its entirety.
• A proximal handle may be attached to the proximal end of the proximal portion and may include imaging devices connected to the fiberoptic imaging bundle for direct viewing and/or for connection to a video camera or a recording device. The handle may be connected to other devices, e.g., illumination sources and one or several luer lock fittings for connection to various instrument channels. The handle may also be connected to a steering control mechanism for controlling the steerable distal portion. The handle may optionally have the steering control mechanism integrated directly into the handle, e.g., in the form of a joystick, conventional disk controller using dials or wheels, etc. An axial motion transducer may also be provided for measuring the axial motion, i.e., the depth change, of the endoscope body as it is advanced and withdrawn. The axial motion transducer can be made in many possible configurations. As the body of the endoscope slides through the transducer, it may produce a signal indicative of the axial position of the endoscope body with respect to the fixed point of reference. The transducer may use various methods for measuring the axial position of the endoscope body.
• The guide is generally used to impart a desired curvature initially defined by the steerable portion and/or by the optional controllable portion to the passive proximal portion when the endoscope is advanced. If held or advanced into the steerable portion, the guide is preferably advanced to or near the distal tip of the portion. It is also used to impart some column strength to the proximal portion in order to maintain its shape and to prevent any buckling when axially loaded. Preferably, the guide is slidably disposed within the length of the endoscope body and may freely slide entirely through the passive proximal portion, through the controllable portion, and the steerable distal portion. The extent to which the guide may traverse through the endoscope body may be varied and adjusted according to the application, as described above. Furthermore, the proximal end of the guide may be routed through a separate channel to a guide controller which may be used to control the advancement and/or withdrawal of the guide and which may also be used to selectively control the rigidity of the guide as controlled by the physician.
• The structure of the guide may be varied according to the desired application. The following descriptions of the guide are presented as possible variations and are not intended to be limiting in their structure. For instance, the guide may be comprised of two coaxially positioned tubes separated by a gap. Once the guide has been placed and has assumed the desirable shape or curve, a vacuum force may be applied to draw out the air within the gap, thereby radially deforming one or both tubes such that they come into contact with one another and lock their relative positions.
• Another variation on the guide is one which is rigidizable by a tensioning member. Such a guide may be comprised of a series of individual segments which are rotatably interlocked with one another in series. Each segment may further define a common channel through which a tensioning member may be positioned while being held between a proximal and a distal segment. During use, the tensioning member may be slackened or loosened enough such that the guide becomes flexible enough to assume a shape or curve defined by the endoscope. When the guide is desirably situated and has assumed a desired shape, the tensioning member may then be tensioned, thereby drawing each segment tightly against one another to hold the desired shape.
• Another variation may use a guide which is comprised of interlocking ball-and-socket type joints which are gasketed at their interfaces. Such a design may utilize a vacuum pump to selectively tighten and relax the individual segments against one another. Other variations may include alternating cupped segments and ball segments, a series of collinear sleeve-hemisphere segments, as well as other designs which may interfit with one another in series. Such a guide may be tightened and relaxed either by tensioning members or vacuum forces.
• A further variation on the guide is a coaxially aligned stiffening member. This assembly may include a first subassembly comprising a number of collinearly nested segments which may be held by a tensioning member passing through each segment. The first subassembly may be rigidized from a flexible or flaccid state by pulling on this tensioning member. A second subassembly may comprise a number of annular segments also collinearly held relative to one another with one or more tensioning members passing through each annular segment. The second subassembly preferably defines a central area in which the first nested subassembly may be situated coaxially within the second subassembly. The first subassembly is preferably slidably disposed relative to the second subassembly thereby allowing each subassembly to be alternately advanced in a flexible state and alternately rigidized to allow the other subassembly to be advanced. This design presents a small cross-section relative to the endoscope or device through which it may be advanced.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows a representation of a conventional endoscope in use.
• FIG. 2A shows a variation of an endoscopic device of the present invention.
• FIGS. 2B and 2C show side sectional views of another variation of the present invention.
• FIG. 3A shows a side view of an endoscopic device variation with the outer layers removed to reveal a guiding apparatus disposed within.
• FIGS. 3B and 3C show cross-sectional views of various examples for obstructing the guide lumen of the endoscope.
• FIGS. 4A to4C show cross-sectional views of various examples of guiding apparatus which may be used to guide an endoscope.
• FIGS. 5A and 5B show the cross-sectioned end and side views, respectively, of a guiding apparatus with a vacuum-actuated rigidizing variation.
• FIGS. 6A and 6B show the cross-sectioned end and side views, respectively, of a guiding apparatus with a tensioning or pre-tensioned element for rigidizing the guide.
• FIGS. 7A and 7B show the cross-sectioned end and side views, respectively, of a guiding apparatus with a segmented vacuum-actuated rigidizing variation.
• FIGS. 8A and 8B show the cross-sectioned end and side views, respectively, of a guiding apparatus with interconnecting jointed segments for rigidizing the guide.
• FIGS. 9A to9C show end, side, and cross-sectioned views, respectively, of another variation on the guiding apparatus.
• FIG. 10 shows the cross-sectioned side view of another variation on the guiding apparatus having alternating bead and sleeve segments.
• FIG. 11A shows a side view of a nested guiding apparatus which is part of a coaxial stiffening assembly.
• FIG. 11B shows a side view of an annular guiding apparatus which is also part of the coaxial stiffening assembly.
• FIG. 11C shows the combination of the guides fromFIGS. 11A and 11B.
• FIGS. 12A and 12B illustrate a representative example of advancing the endoscope along a tortuous pathway using a single rigidizing step.
• FIGS. 13A to13H illustrate a representative example of advancing an endoscope through a patient's colon using a guiding apparatus to assist in advancing the endoscope.
• FIGS. 14A and 14B show a variation on the withdrawal of the endoscope with or without the guiding apparatus for the selective treatment of sites along the patient's colon.
• FIGS. 15A to15C illustrate a representative example of advancing an endoscope through a tortuous path using the coaxial guiding apparatus shown inFIGS. 11A to11C.
• FIGS. 16A to16E illustrate another variation of advancing an endoscope through a tortuous path using multiple guiding apparatuses.
DETAILED DESCRIPTION OF THE INVENTION
• FIG. 1 shows aprior art colonoscope10 being employed for a colonoscopic examination of a patient's colon C. Thecolonoscope10 has aproximal handle16 and anelongate body12 with a steerabledistal portion14. Thebody12 of thecolonoscope10 has been lubricated and inserted into the colon C via the patient's anus A. Utilizing the steerabledistal portion14 for guidance, thebody12 of thecolonoscope10 has been maneuvered through several turns in the patient's colon C to the ascending colon G. Typically, this involves a considerable amount of manipulation by pushing, pulling and rotating thecolonoscope10 from the proximal end to advance it through the turns of the colon C. After the steerabledistal portion14 has passed, the wall of the colon C maintains the curve in theflexible body12 of thecolonoscope10 as it is advanced. Friction develops along thebody12 of thecolonoscope10 as it is inserted, particularly at each turn in the colon C. Because of the friction, when the user attempts to advance thecolonoscope10, thebody12′ tends to move outward at each curve, pushing against the wall of the colon C, which exacerbates the problem by increasing the friction and making it more difficult to advance thecolonoscope10. On the other hand, when thecolonoscope10 is withdrawn, thebody12″ tends to move inward at each curve taking up the slack that developed when thecolonoscope10 was advanced. When the patient's colon C is extremely tortuous, the distal end of thebody12 becomes unresponsive to the user's manipulations, and eventually it may become impossible to advance thecolonoscope10 any farther. In addition to the difficulty that it presents to the user, tortuosity of the patient's colon also increases the risk of complications, such as intestinal perforation.
• FIG. 2A shows a variation of thesteerable endoscope20 of the present invention. Theendoscope20 has anelongate body21 with a manually or selectively steerabledistal portion24, an automatically controlledportion28, which may be optionally omitted from the device, a flexible and passively manipulatedproximal portion22, and an externally controlled and manipulatable tracking rod or guide36 which may be slidably positioned within theendoscope20.
• The selectively steerabledistal portion24 can be selectively steered or bent up to a full 180° bend in anydirection26, as shown in the figure. Afiberoptic imaging bundle40 and one ormore illumination fibers42 may extend through thebody21 from theproximal portion22 to thedistal portion24. Alternatively, theendoscope20 may be configured as a video endoscope with a miniaturized video camera, such as a CCD camera, positioned at thedistal portion24 of theendoscope body21. The images from the video camera can 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, thebody21 of theendoscope20 may include one or twoaccess lumens38 that may optionally be used for illumination fibers for providing a light source, insufflation or irrigation, air and water channels, and vacuum channels. Generally, thebody21 of theendoscope20 is 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, thebody21 of theendoscope20 may range typically from 135 to 185 cm in length and about 13-21 mm in diameter. Theendoscope20 can be made in a variety of other sizes and configurations for other medical and industrial applications.
• The optionalcontrollable portion28 is composed of at least onesegment30, and preferablyseveral segments30, which may be controllable via a computer and/or controller located at a distance from theendoscope20. Each of thesegments30 preferably has an actuator mechanically connectingadjacent segments30 to allow for the controlled motion of thesegments30 in space. The actuators driving thesegments30 may include a variety of different types of mechanisms, e.g., pneumatic, hydraulic, electromechanical motors, “off board” powered drive shafts, tendons, etc. Aproximal portion22 comprises the rest of theendoscope20 and preferably a majority of the overall length of thedevice20.Proximal portion20 is preferably a flexible tubing member which may conform to an infinite variety of shapes. It may also be covered by a polymeric covering39 optionally extendable overcontrollable portion28 and steerabledistal portion24 as well to provide a smooth transition between thecontrollable segments30 and the flexible tubing ofproximal portion22. Theproximal portion22 may be made from a variety of materials such as thermoset and thermoplastic polymers which are used for fabricating the tubing of conventional endoscopes.
• Aproximal handle32 may be attached to the proximal end of theproximal portion22. Thehandle32 may include an ocular33 connected to thefiberoptic imaging bundle42 for direct viewing. Thehandle32 may otherwise have a connector for connection to a video camera, e.g., a CCD camera, or a recording device. Thehandle32 may be connected to anillumination source43 by anillumination cable44 that is connected to or continuous with theillumination fibers42. One or severalluer lock fittings34 may be located on thehandle32 and connected to the various instrument channels.
• Thehandle32 is connected to anelectronic motion controller45 by way of acontroller cable46. Asteering control47 may be connected to theelectronic motion controller45 by way of asecond cable48 or it may optionally be connected directly to thehandle32. Alternatively, the handle may have the steering control mechanism integrated directly into the handle, e.g., in the form of a joystick, conventional disk controllers such as dials or wheels, etc. Thesteering control47 allows the user to selectively steer or bend the selectively steerabledistal portion26 of thebody21 in the desired direction. Thesteering control47 may be a joystick controller as shown, or other known steering control mechanism. Theelectronic motion controller45 controls the motion of the automatically controlledproximal portion28 of thebody21. Theelectronic motion controller45 may be implemented using a motion control program running on a microcomputer or using an application-specific motion controller. Alternatively, theelectronic motion controller45 may be implemented using, e.g., a neural network controller.
• Anaxial motion transducer49 may be provided for measuring the axial motion, i.e., the depth change, of theendoscope body21 as it is advanced and withdrawn. Theaxial motion transducer49 can be made in many possible configurations. For example, theaxial motion transducer49 inFIG. 2A is configured as aring49 that may surround thebody21 of theendoscope20. Theaxial motion transducer49 is preferably attached to a fixed point of reference, such as the surgical table or the insertion point for theendoscope20 on the patient's body. As thebody21 of theendoscope20 slides through theaxial motion transducer49, it produces a signal indicative of the axial position of theendoscope body21 with respect to the fixed point of reference and sends a signal to theelectronic motion controller45 by telemetry or by a cable. Theaxial motion transducer49 may use optical, electronic or mechanical methods to measure the axial position of theendoscope body21.
• Similarly, when theendoscope body21 is withdrawn proximally, each time theendoscope body21 is moved proximally by one unit, each section in the automatically controlledproximal portion28 is signaled to assume the shape of the section that previously occupied the space that it is now in. The curve propagates distally along the length of the automatically controlledproximal portion28 of theendoscope body21, and the shaped curve appears to be fixed in space, as theendoscope body21 withdraws proximally. Alternatively, the segments of controlledportion28 could be made to become flaccid and the withdrawal would then be passive.
• Whenever theendoscope body21 is advanced or withdrawn, theaxial motion transducer49 detects the change in position and theelectronic motion controller45 propagates the selected curves proximally or distally along thecontrollable portion28 of theendoscope body21 to maintain the curves in a spatially fixed position. Theaxial motion transducer49 also allows for the incrementing of a current depth within the colon C by the measured change in depth. This allows theendoscope body21 to be guided through tortuous curves without putting unnecessary force on the wall of the colon C. As mentioned above, such asegmented body30 within thecontrollable portion28 may be actuated by a variety of methods. One method involves the use of electromechanical motors which may be individually mounted on eachsegment30 to move thesegments30 relative to one another. Eachsegment30 preferably defines at least one lumen running through it to provide an access channel through which wires, optical fibers, air and/or water channels, various endoscopic tools, or any variety of devices and wires may be routed through.
• A more detailed description on the construction and operation of the segments may be found in U.S. patent application Ser. No. 09/969,927 entitled “Steerable Segmented Endoscope and Method of Insertion” filed Oct. 2, 2001, which has been incorporated by reference in its entirety.
• Theguide36 is generally used to impart a desired curvature initially defined by the steerabledistal portion24 and/or by the optionalcontrollable portion28 to the passiveproximal portion22 when theendoscope20 is advanced. If theguide36 is advanced into the steerabledistal portion24, guide36 is preferably advanced to or near the distal tip of theportion24. Theguide36 may also be used partly to impart some column strength to theproximal portion22 in order to maintain its shape and to prevent any buckling when axially loaded, such as when theendoscope20 is advanced through a patient's colon. Construction of anendoscope20 with the use of theguide36 not only simplifies the control systems involved but it also represents a cost efficient device. Operation of theendoscope20 withguide36 will be discussed in detail below.
• Preferably, theguide36 is slidably disposed within the length of theendoscope body21 and may freely slide entirely through the passiveproximal portion22, through the optionalcontrollable portion28, if utilized in the endoscope, and the steerabledistal portion24.Guide36 may also be withdrawn through the instrument to any location within the body ofendoscope20. Moreover, guide36 may be removed entirely fromendoscope20, if desired e.g., to accommodate additional working tools. In other words, there are preferably no constraints which may limit the travel ofguide36 within the body ofendoscope20.
• Guide36 may be advanced throughproximal handle32; alternatively, guide36 may also be routed through aseparate channel37 dedicated to theguide36.Channel37 is preferably attached toendoscope20 near a proximal end of the instrument, such as a location off theproximal portion22, and leads to aguide controller41 which may be used to advance and/or withdrawguide36 throughendoscope20.Guide controller41 may also be used to selectively rigidize and relaxguide36 during use within a patient. Havingguide controller41 andproximal handle32 separated may allow for the ease of use for the physician manipulating theendoscope20. To aid in advancingguide36 throughendoscope20, a pulley mechanism may be affixed within the steerabledistal portion24 through which a pull wire may extend over to connect the distal end of theguide36 to a location outside theendoscope20 for manipulation by the physician.
• To facilitate the movement ofguide36 throughendoscope body21, a lubricious covering or coating may be applied over at least a majority of the length ofguide36 or onto the inner surface of the lumen through which guide36 traverse, or both. Such coverings may include various polymers and plastics, e.g., PTFE, etc., which may simply cover theguide36 length or which may be heatshrunk, coated, or bonded ontoguide36, depending upon the material used. The extent to which guide36 traverses through theendoscope body21 may be varied and adjusted according to the application.
• FIGS. 2B and 2C show sectional partial views of a variation of the endoscope that is capable of single-step use of the guide. In these variations, the axial length of theguide51 is shorter than the insertable length of theendoscope23. Theendoscope body21 includes a steerabledistal tip24 and a proximalcontrollable region28 that is comprised offlexible segments30. Approximately half of the length of the endoscope body may be composed ofcontrollable segments30, and the remaining proximal part of the endoscope is flexiblepassive portion22. The length of theguide51 is approximately half that of theendoscope body23. Although theguide51 is freely slidable withinlumen50 of theendoscope23 in the variation shown, theguide51 may be preloaded through the distal end of theendoscope23 before insertion into the body. Alternatively, theguide51 could be positioned as described above. Theguide51 can be rigidized and held in place by thetensioning wire36. The combination of steerabledistal tip24, controllableproximal portion28 and guide51 in this variation of the invention simplifies the use of the rigidizable guide51 because theguide51 only has to be rigidized and locked into position once.
• FIG. 2C shows another, slightly magnified, sectional view of the endoscope ofFIG. 2B. This view illustrates an optional suction device53, e.g., a negative pressure pump device, which may be fluidly connected tosuction port202 through suction tube204. Suction device53 is preferably located externally of the patient during use. Because insufflated air or gas may be trapped within regions of the colon due to the sacculation and movement of the colon walls, the suction device53 may be used to facilitate removal of these gases as the endoscope is advanced or withdrawn through the colon. Thesuction port202 shown is preferably located at some point proximal ofdistal end24, e.g., approximately one quarter of the length of theendoscope body23. This suction port can be located virtually anywhere along the length of the endoscope, but it is preferably located such that it does not interfere with the insufflation process at or near the distal tip.
• FIG. 3A shows an isometric view of a length of theendoscope20, in this example part of theproximal portion22, with a section of theendoscope body20 removed for clarity. As seen, a representative illustration of theguide36 may be seen disposed within guide channel orlumen50 within theproximal portion22.Lumen50 may be an existing working channel, i.e., an access channel for other tools, or it may be a designated channel forguide36 depending upon the desired application.Guide36 may be inserted withinguide channel50 through the endoscope handle32 and pushed proximally through the remainder of the device, as seen inFIG. 2A; or preferably, it may be pushed proximally or pulled distally, as necessary, through aseparate guide controller41, as discussed above. Althoughguide36 is shown in this variation as being slidably disposed interiorly ofendoscope body20, it may also be disposed exteriorly of thebody20 to slide along a guide rail or exterior channel in other variations.
• Ifguide36 is located within a dedicated channel, such aslumen50, the distal end of this channel is preferably closed or blocked at some distal location, e.g., within steerabledistal portion24 or within optionalcontrollable portion28, to prevent the influx of bodily fluids withinlumen50. Because anenclosed lumen50 would further prevent contact of bodily fluids withguide36, the amount of cleaning or sterilization ofguide36 is reduced.
• Iflumen50 were left as an open channel, additional sterilization or cleaning and disinfecting ofguide36 andlumen50 may be necessary. Alternatively,lumen50 may be left as an open channel but configured to have optional closing mechanisms, as shown in the examples ofFIGS. 3B and 3C, taken fromFIG. 3A.FIG. 3B shows an end view of a trap or door54 which is held within the body of the instrument and which may be rotated about apivot56 in the direction of the arrow to close access tolumen50. Trap54 may be closed during insertion of the instrument within a patient and then optionally opened to allow for working tools to be inserted therethrough.FIG. 3C shows another example wherelumen50 may be obstructed by aninflatable balloon59 which may selectively expand to completely obstruct the passageway.Balloon59 may be made of conventional materials and may be held within a compartment or step58 such thatlumen50 is unobstructed whenballoon59 is deflated. These examples merely present variations and are not meant to limit the scope of the invention. Alternative designs and variations are intended to be within the scope of the present invention.
• FIGS. 4A to4C show variations onpossible cross-sections4A-4A,4B-4B, and4C-4C, respectively, taken fromFIG. 3A.FIG. 4A shows asimplified cross-section22′ of aguide36 having a circular diameter slidably disposed withinproximal portion22. As seen, guide36 may be slidably positioned withinchannel50′, which may also be used as a working channel upon removal ofguide36 during, e.g., a colonoscopy procedure, for providing access for various instruments or tools to a treatment site.FIG. 4B shows another possible variation incross-section22″ whereguide36 is positioned withinchannel50″. The variation of the proximal portion incross-section22″ may include a number ofaccess lumens52 optionally formed within the body of thedevice20. Theselumens52 may run through the length ofdevice20 and may be used for various applications, e.g., illumination fibers, laparoscopic tools, etc. Although threelumens52 are shown in the figure, any number of channels as practically possible may be utilized depending upon the application at hand.FIG. 4C shows another variation incross-section22′″. In this variation, guide36′ may be formed into a semi-circular or elliptical shape to slide within a similarly shapedchannel50′″. In this example,proximal portion22′″ also includes a workingchannel52′ which may be shaped accordingly to fit within thebody22′″ along withchannel50′″ to maintain a working channel without having to removeguide36′. In any of the above examples, the working or guide channels are preferably integral structures within the body ofendoscope20. Having an integral structure eliminates the need for a separate lumened structure, e.g., a separate sheath, through which guide36 or any other tools may be inserted. Another variation utilizing multiple channels and multiple guides will be described in further detail below. These variations are not intended to be limiting but are merely presented as possible variations. Other structures and variations thereof may be recognized by one of skill in the art and are intended to be within the, scope of the claims below.
• The structure of the guide may be varied according to the desired application. The following description on the guide is presented as possible variations and are not intended to be limiting in their structure.FIGS. 5A and 5B show cross-sectioned end and side views, respectively, of a guiding apparatus variation which is rigidizable by a vacuum force applied within the guide. It is preferable that the guide is selectively rigidizable, i.e., when the guide assumes a shape or curve in a flexible state, the guide may be rigidized to hold that shape or curve for a predetermined period of time. Although the endoscope structure of the present invention may utilize a guide which remains in a relatively flexible shape, it is preferable to have the guide be selectively rigidizable.
• Guide60 may be comprised of two coaxially positioned tubes,outer tube62 andinner tube64, which are separated by agap66 between the two tubes.Inner tube64 may define anaccess lumen68 throughout the length of the tube to provide a channel for additional tools or other access devices. Bothtubes62,64 are preferably flexible enough to be bent over a wide range of angles and may be made from a variety of materials such as polymers and plastics. They are also preferably flexible enough such that either theouter tube62,inner tube64, or both tubes are radially deformable. Onceguide60 has been placed and has assumed the desirable shape or curve, a vacuum force may be applied to draw out the air withingap66. This vacuum force may radially deforminner tube64 and bring it into contact with the inner surface ofouter tube62 ifinner tube64 is made to be relatively more flexible thanouter tube62. Alternatively, ifouter tube62 is made to be relatively more flexible thaninner tube64,outer tube62 may be brought into contact with the outer surface ofinner tube64.
• In another variation,tubes62,64 may both be made to be flexible such that they are drawn towards one another. In yet another variation, which may be less preferable, a positive force of air pressure or a liquid, e.g., water or saline, may be pumped intoaccess lumen68. The positive pressure from the gas or liquid may force the walls ofinner tube64 radially into contact with the inner surface ofouter tube62. In any of these variations, contact between the two tubular surfaces will lock thetubes62,64 together by frictional force and make them less flexible. An elastomeric outer covering69, or similar material, may optionally be placed upon the outer surface ofouter tube62 to provide a lubricious surface to facilitate the movement ofguide60 within the endoscopic device. An example of a device similar to guide60 is discussed in further detail in U.S. Pat. No. 5,337,733, which has been incorporated herein by reference in its entirety.
• Another variation on the guide is shown inFIGS. 6A and 6B which show cross-sectioned end and side views, respectively, of a guidingapparatus variation70 which is rigidizable by a tensioning member76.Tensioned guide70 is shown comprised of a series ofindividual segments72 which are rotatably interlocked with one another in series. Eachsegment72 may contact an adjoiningsegment72 along a contactinglip78. Eachsegment72 may further define a channel therethrough which, collectively along with theother segments72, form acommon channel74 throughout a majority of the length ofguide70.Segments72 may be comprised of a variety of materials suitable for sustaining compression forces, e.g., stainless steel, thermoplastic polymers, plastics, etc.
• Proximal and distal segments ofguide70 may hold respective ends of tensioning member76, which is preferably disposed withincommon channel74 throughguide70. Tensioning member76 may be connected to a tensioning housing located externally of a patient. During use when the guide is advanced distally through an endoscope of the present invention, tensioning member76 is preferably slackened or loosened enough such that guide70 is flexible enough to assume a shape or curve defined by the endoscope. Whenguide70 is desirably situated and has assumed a desired shape, tensioning member76 may be tensioned. This tightening or tensioning of member76 will draw eachsegment72 tightly against one another along each respective contactinglip78 such that theguide70 becomes rigid in assuming the desired shape. A lubricious covering, e.g., elastomers, etc., may be optionally placed over at least a majority ofguide70 to facilitate movement of theguide70 relative to the endoscopic device. A similar concept and design is discussed in further detail in U.S. Pat. No. 5,624,381, which has been incorporated herein by reference in its entirety.
• FIGS. 7A and 7B show cross-sectioned end and side views, respectively, of a guiding apparatus variation80 which is rigidizable by a vacuum force which interlocksindividual segments82. Eachsegment82 may be adjoined with adjacent segments by interlocking ball-and-socket type joints which are preferably gasketed at theinterfaces86 of each connection. Within eachsegment82, with the exception of the distal segment, may be defined a channel which is narrowed at one end and flared at the opposite end. Collectively when thesegments82 are adjoined into the structure of guide80, each of the individual channels form acommon channel84 which extends through at least a majority of thesegments82 along the length of guide80. At the proximal end of guide80 a vacuum pump, which is preferably located externally of the patient, is fluidly connected tocommon channel84. In use, once guide80 is manipulated in its flexible state within the endoscope to assume the desired shape or curve, ambient pressure may exist withincommon channel84. When the rigid shape of guide80 is desired, the pump may then be used to create a negative pressure withincommon channel84 and this negative pressure draws eachsegment82 into tight contact with one another to maintain the desired shape. When the vacuum force is released, eachsegment82 would also be released and would thereby allow the guide80 to be in its flexible state for advancement or withdrawal. Guide80 may further be surrounded by an elastomeric or lubricious covering to aid in the advancement or withdrawal of the guide80 within the endoscopic device.
• FIGS. 8A and 8B show cross-sectioned end and side views, respectively, of yet another guiding apparatus variation90 which is optionally rigidizable by either a vacuum force or a tensioning member which interlocksindividual segments92.Segment92 may be in the form of a segmented design with two opposed cups having acommon channel94 defined therethrough. Between eachsegment92 areball segments96 which interfits along a contact rim orarea97 within eachadjacent segment92.Ball segments96 preferably contact adjacentcupped segments96 within receivingchannels98 defined in each cup. When manipulated in its flexible state, guide90 may be advanced or withdrawn or made to assume a desired shape or curve. When guide90 is to be placed into its rigidized shape, a vacuum force or tensioningmember99 may be utilized in the guide90 in similar manners as described above. Moreover, guide90 may similarly be surrounded by an elastomeric or lubricious covering to aid in the advancement and withdrawal of the guide90.
• FIGS. 9A and 9B show representative end and side views, respectively, of another guidingapparatus variation100. Thisvariation100 comprisesindividual segments102 having auniform sleeve section104 in combination with an integrated curved orhemispherical section106. Eachsegment102 is collinearly aligned with one another with thesleeve section104 receiving thecurved section106 of anadjacent segment102, as shown inFIG. 9C, which is the cross-section ofguide100 fromFIG. 9B. Theadjacent segments102 may rotate relative to one another over the sleeve-hemisphere interface while maintaining acommon channel108 through theguide100. A tensioningmember110 may pass throughchannel108 along the length ofguide100 for compressing theindividual segments102 against one another when theentire guide100 is rigidized.
• FIG. 10 shows the cross-section of anothervariation120 of the rigidizable guide apparatus. Representative segments are shown comprisingspherical bead segments122 alternating withsleeve segments124. Each of the bead andsleeve segments122,124, respectively, may have a channel defined therethrough which allows for atensioning member126 to be run through the length ofguide120. The alternating segments allow for the rotation of the adjacent segments while the tensioningmember126 allows for the compression of the segments against one another when theguide120 is to be rigidized in much the same manner as described above.
• An alternative variation on the rigidizable guide is illustrated inFIGS. 11A to11C, which show a stiffening assembly having separate rigidizable coaxially positioned guides.FIG. 11A shows a representative number of nestedsegments132 in nestedstiffening assembly130. Each nestedsegment132 may be in a number of different configurations, e.g., ball socket joints, stacked ring-like segments, etc., with atensioning member134 passing through each of thesegments132. For use with nestedassembly130, anannular stiffening assembly140 may be seen inFIG. 11B.Annular assembly140, of which only a few representative segments are shown, are comprised in this variation ofannular segments142 which may be stacked or aligned one atop each other. At least one tensioningmember144, and preferably at least two, may be passed through each of theannular segments142. Acentral area146 is defined in eachannular segment142 such that nested stiffeningassembly130 may be slidingly placed within thecentral area146 defined by theannular stiffening assembly140.FIG. 11C shows the stiffeningassembly130 slidingly positioned withinannular stiffening assembly140 to form the coaxially aligned stiffeningassembly150. Use ofcoaxial assembly150 will be described in further detail below.
• FIGS. 12A and 12B illustrate a variation of the endoscope advancing through a tortuous path, using an endoscope similar to the variation ofFIG. 2B.FIG. 12A shows a pathway withmultiple turns210, resembling a length of the colon. The distal half of thedevice212 comprises a steerabledistal portion24 and a controllableproximal portion28. Theguide51 is slidably held within a lumen within the endoscope in the relaxed state. As thedevice212 is advanced into thepathway210, the user steers thedistal tip24, and thecontrollable segments30 follow the curve selected by the user, navigating the chosen pathway. While in the relaxed state, theguide51 may passively assume the shape taken by thedistal portion24 and the controllableproximal portion28 as they are steered along the path. Usually, the user may rigidize and/or “lock” theguide51 to assume the curve of the selected pathway before the controllableproximal portion28 has advanced beyond thefirst curve220. After being stiffened and locked into position, the endoscope can continue moving distally while still maintaining the selected pathway, since the passive flexibleproximal region22 of the endoscope slides over therigid guide51 and conforms to its shape, as shown inFIG. 12B.
• After rigidizing the guide, the user can continue to steer thedistal end24 as it is advanced, and the curves of the selected pathway are propagated proximally down thecontrollable segments30 as the endoscope moves forward. This variation of the device is capable of conforming to a selected pathway over the entire length of the endoscope, despite having ashorter guide51 andcontrollable portion28, since the combined length of theguide51 and the controllable portion is preferably equal to the length of the endoscope.
• In operation, any of the guiding apparatus as described above or one recognized by a person of skill in the art to be suitable for such use as described herein may be utilized.FIGS. 13A to13H illustrate a representative method of advancing acolonscopic device20 as described herein with arepresentative guide36 for advancement into a patient's colon C. As seen inFIG. 13A, the steerabledistal portion24 ofcolonoscope20 may be first advanced into the patient's rectum via anus A. Thedevice20 may be simply advanced, either manually or automatically by a motor, until the first curvature is reached or alternatively until the segments ofcontrollable portion28 are within colon C. At this point, the steerabledistal portion24 may be actively controlled by the physician or surgeon to attain an optimal curvature or shape for advancement ofdevice20. The optimal curvature or shape is considered to be the path which presents the least amount of contact or interference from the walls of colon C. If the optionalcontrollable portion28 is used with thecolonoscopic device20, once theadvancement position160 has been determined, thedevice20 may be advanced further into the sigmoid colon S such that the automatically controlled segments ofcontrollable portion28 follow thedistal portion24 while transmitting the optimal curvature or shape proximally down the remaining segments ofcontrollable portion28.
• Alternatively, once steerabledistal portion24 has been steered or positioned foradvancement160, guide36 may be advanced distally in its flexible state along or withindevice20 until it reaches a distal position, i.e., some point distal of the flexibleproximal portion22 and preferably to the distal end of thedevice20, as shown inFIG. 13B. Preferably, guide36 is advanced to the distal end of steerabledistal portion24 or to the distal end of the optionalcontrollable portion28, if utilized, or to some point therebetween.Guide36 may be advanced to any distal position as long as a portion ofguide36 attains the optimal curvature or shape. Prior to advancing thedevice20 overguide36, theguide36 may be left in its flexible state or it may be optionally rigidized, as discussed above. If left in its flexible state, guide36 will still provide desirable column strength to thedevice20 as it is advanced through colon C over theguide36. It is preferable, however, thatguide36 is rigidized once it has attained and conformed to the curvature. As the position ofguide36 is preferably rigidized and maintained, thedevice20 may then be advanced over theguide20 in a monorail or “piggy-back” fashion so that the flexibleproximal portion22 follows the curve held byguide36 until thedevice20 reaches the next point of curvature. The following description discusses the use of the optionalcontrollable portion28; however, thisportion28 may be omitted from thedevice20.
• As shown fromFIGS. 13B to13C, the curve is maintained byguide36 until the steerabledistal portion24 has been advanced to the juncture between the sigmoid colon S and the descending colon D. At this point, thedistal portion24 may be actively steered by the physician using a variety of visualization techniques, e.g., steering via anoptional imaging bundle40 located at the distal end of thedevice20. Once the optimal curve or shape has been determined, thedevice20 may be advanced toposition160. As the device is moved distally, if thecontrollable portion28 is utilized,portion28 will automatically follow the path set by the distal portion while the flexible proximal portion follows thedevice20 along the curvature defined by theguide36. Otherwise, ifcontrollable portion28 is omitted, guide36 will have its curvature defined solely by steerabledistal portion24. Once the junction between the sigmoid colon S and descending colon D has been traversed by the steerabledistal portion24 and the optionalcontrollable portion28, the guide may then be relaxed and advanced distally along thedevice20 in its flexible state until it reaches the distal position in thedevice20. As theguide36 is advanced, it will attain and conform to a new curvature defined by the steerabledistal portion24 and/or thecontrollable portion28, as shown inFIG. 13D.
• Having attained a new curvature, guide36 may again be rigidized to maintain this shape. While theguide36 maintains this shape, thedevice20 may be advanced further distally along the descending colon D with the help of therigidized guide36 in the piggy-back manner described above to define the path for the flexibleproximal portion22 and to prevent excessive contact with the walls of colon C. As shown inFIG. 13E, thedevice20 has been advanced past the left (splenic) flexure F_lin the manner described above until the optionalcontrollable portion28 has attained the optimal curvature. Theguide36 may be relaxed again and advanced further distally in its flexible state, as shown fromFIGS. 13E to13F.
• Afterguide36 has assumed the desired curvature defined by thedistal portion24 and/orcontrollable portion28, as shown inFIG. 13F, it may again be rigidized and thedevice20 may then be advanced through the transverse colon T and around the right (hepatic) flexure F_rin much the same manner as described above and as shown inFIG. 13G. Once thedistal portion24 and the optionalcontrollable portion28 has controllably negotiated past the right (hepatic) flexure F_r, the position ofguide20 may again be maintained whileguide36 is relaxed once again and advanced distally to assume the new curvature defined bydistal portion24 and/orcontrollable portion28, as shown inFIG. 13H. Afterguide36 is optionally rigidized again,device20 may be advanced160 completely within the ascending colon G towards the cecum E for a complete examination of the colon C with minimal complication and effort.
• While thedevice20 is advanced through the colon C, the physician or surgeon may stop the advancement to examine various areas along the colon wall using, e.g., theimaging bundle40. During such examinations, theguide36 may be temporarily withdrawn manually or automatically from thedevice20 to allow for the insertion of other tools through theguide channel50. After a procedure has been completed on the colon wall, the tool may be withdrawn fromguide channel50 and guide36 may be reintroduced into thedevice20 so that the device may optionally be advanced once again into colon C.
• To withdrawdevice20 from within the colon C, the procedure above may be reversed, as shown inFIG. 14A, such that thewithdrawal162 minimally contacts the walls of colon C. Alternatively, guide36 may simply be removed fromdevice20, as shown inFIG. 14B, while leavingdevice20 within colon C. Thedevice20 may simply be withdrawn by pulling theproximal portion22 to remove thedevice20. This method may rub or contact thedevice20 upon the walls of colon C, but any impingement would be minimal.
• An alternative method of advancing an endoscope through a tortuous path may be seen inFIGS. 15A to15C by using the rigidizable guide assembly150 seen fromFIG. 11C.FIG. 15A shows a pathway to be negotiated byendoscopic device172. The pathway may represent a portion ofcolon170. Asdevice172 is desirably steered to assume a curve, nested stiffeningassembly130 may be advanced distally withindevice172 todistal end174 while in a relaxed state. Alternatively, nestedassembly130 may be advanced in the flexible, relaxed state along with thedistal end174.
• Once the curve has been selected, nestedassembly130 may be stiffened to maintain its shape. At this point,annular stiffening assembly140 may be advanced over nestedassembly130 towardsdistal end174. Onceassembly140 has assumed the curve defined byassembly130,annular assembly140 may then be rigidized and nestedassembly130 may be relaxed into its flexible state, as shown inFIG. 15B. Then thedistal end174 may be further advanced with or withoutassembly130 while being pushed along the curve defined by rigidizedannular assembly140, as shown inFIG. 15C. Oncedistal end174 ofdevice172 has negotiated the curve, nestedassembly130, after being advanced todistal end174, may then be rigidized again andannular assembly140 may be relaxed and advanced again overassembly130 and so on until the desired treatment location has been reached within the body.
• Another alternative variation on advancing an endoscope through a tortuous path may be seen inFIGS. 16A to16E. This variation uses multiple guides which may be alternately rigidized while being advanced distally along the path.FIG. 16A shows a portion of the curved pathway incolon170 withendoscope180 being advanced therethrough. Multiple guides may be used in this variation, but preferably two guides are utilized, as described below. Any one of the rigidizable guide variations discussed herein may be used solely or in combination with different types of guides in thesame device180. Each guide may be advanced within its own lumen defined within the endoscope, or they may also share a common dedicated lumen.
• Asdevice180 approaches a curvature ofcolon170,first guide184 maybe advanced towards the steerabledistal end182. While being advanced,first guide184 is in a relaxed and flexible state allowing it to conform to the shape defined by thedistal end182. Having been advanced todistal end182, as shown inFIG. 16B,first guide184 is rigidized to maintain the shape defined by the steerabledistal end182.Device180 may then be advanced further distally intocolon170 while riding over rigidizedfirst guide184.
• Afterdevice180 has been further advanced to a new position,second guide186 may also be advanced distally in its relaxed state throughdevice180 up to thedistal end182 whilefirst guide184 is preferably still rigidized, as shown inFIG. 16C. Assecond guide186 advances, it may conform to a new shape defined bydevice180.Second guide186 may then be rigidized to hold its shape.First guide184 may be relaxed but its rigid shape is preferably also maintained while thedistal end182 ofdevice180 is further advanced distally throughcolon170, as shown inFIG. 16D.
• Afterdevice180 has been advanced distally,first guide184 may be relaxed and advanced throughdevice180 up todistal end182 while the rigidity ofsecond guide186 is maintained, as shown inFIG. 16E.Second guide186 may be relaxed and then advanced in its flexible state distally throughdevice180 and so on. This process may be repeated asdevice180 is required to negotiate arbitrarily tortuous paths.
• Although the endoscope of the present invention has been described for use as a colonoscope, the endoscope can be configured for a number of other medical and industrial applications. In addition, the present invention can also be configured as a catheter, cannula, surgical instrument or introducer sheath that uses the principles of the invention for navigating through tortuous body channels. The present invention may also be used for industrial applications such as inspection and exploratory applications within tortuous regions, e.g., machinery, pipes, etc.
• In a variation of the method that is particularly applicable to laparoscopy or thoracoscopy procedures, the steerable endoscope can be selectively maneuvered along a desired path around and between organs in a patient's body cavity. The distal end of the endoscope may be inserted into the patient's body cavity through a natural opening, through a surgical incision or through a surgical cannula, introducer, or trocar. The selectively steerable distal portion can be used to explore and examine the patient's body cavity and to select a path around and between the patient's organs. The electronic motion controller in conjunction with the tracking rod can be used to control the automatically controlled proximal portion to follow the selected path and allow the rest of the body to follow the tracking rod and, if necessary, to return to a desired location using the three-dimensional model in the electronic memory of the electronic motion controller. 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)

1-34. (canceled)

35. A method for advancing a first diagnostic or therapeutic instrument having a steerable distal tip into an unsupported, hollow body organ, the method comprising:

providing an apparatus having a handle, an overtube coupled to the handle, the 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 unsupported, hollow body organ by steering the steerable distal tip of the first diagnostic or therapeutic instrument, thereby deflecting the flexible distal region of the overtube.

36. The method ofclaim 35 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.

37. The method ofclaim 36 wherein providing an apparatus comprises providing an apparatus 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.

38. The method ofclaim 36 wherein providing an apparatus comprises providing an apparatus 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.

39. The method ofclaim 35 further comprising deflecting the unsupported, hollow body organ 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.

40. The method ofclaim 35, wherein providing an apparatus comprises providing an apparatus wherein the lumen is dimensioned to permit passage of a second diagnostic or therapeutic instrument alongside the first diagnostic or therapeutic instrument, the method further comprising:

advancing the second diagnostic or therapeutic instrument alongside the first diagnostic or therapeutic instrument.

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