Patent Publication Number: US-11659983-B2

Title: Expanding endoscope and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 15/502,570, filed Feb. 8, 2017, which is a U.S. National Stage Application under 35 U.S.C. § 371(a) of PCT/US2016/019353 filed Feb. 24, 2016, which claims the benefit of U.S. Provisional App. Ser. No. 62/121,752 filed Feb. 27, 2015, titled “Expanding endoscope with nested components to minimize diameter during insertion,” and also claims the benefit of U.S. Provisional App. Ser. No. 62/201,168 filed Aug. 5, 2015, titled “Expanding endoscope and method.” All of the above-listed applications are incorporated by reference herein as if reproduced in full below. 
    
    
     FIELD 
     The present disclosure relates to the field of surgical instruments, and more particularly relates to surgical instruments and methods for endoscopically viewing tissue. Embodiments include laterally shifting a distal end of a camera from a first position to a second position without obstructing a view from the distal end of the camera while shifting between the first and second positions. 
     BACKGROUND 
     A “working” section of a medical endoscope may be a distal portion of the endoscope that is inserted into a patient, either through another instrument, or directly into an orifice, incision, or other entry point. In surgical applications, it is often desirable to decrease a working section diameter of instruments to reduce trauma and discomfort to a patient. An endoscope has a diameter that is large enough to contain all of the endoscope&#39;s functional components adjacent to one another. These components may include structural and protective members, optical elements, fibers to transfer light for illumination, and channels for instruments or fluid flow. Often a reduction in cross-sectional area of a given component translates into a reduction in functionality or performance of that component. Reducing the size of structural elements may reduce structural integrity and robustness. Smaller optical elements may result in reduced image quality. Fewer or smaller illumination fibres may lead to lower image brightness. Smaller channels may limit instrument compatibility and reduce the rate of fluid flow available to clear debris from an operative field. Consequently, a fundamental trade-off has typically existed in endoscope design between working section diameter and performance. One way to address these inherent limitations is to rigorously assess the functional requirements of the procedure and the needs of the customer to determine the optimal combination of size, functionality, and performance for a given application. Another approach is to develop smaller components that maintain the same or similar functionality and performance. For example, the size of rod lenses has been reduced while maintaining their optical performance. Miniaturized instruments have been developed that engage tissue with the same efficiency as larger devices. Alternative optical technologies, including fibre optic bundles and “chip-on-a-stick” cameras, have been developed that are less fragile and reduce the need for scope structural integrity. Additionally, the relationships between various components may be engineered to decrease overall endoscope size. However, many of these types of advancements present significant cost challenges. 
     SUMMARY 
     One embodiment is an endoscope that includes a camera configured to electrically couple to one or more instruments external to the endoscope and a tubular enclosure through which a surgical act may be performed. The tubular enclosure may have a central longitudinal axis, and the camera and the tubular enclosure of some embodiments are movably coupled to one another. In a first coupled position, a distal end of the camera is positioned on the central longitudinal axis of the tubular enclosure, and in a second coupled position the distal end of the camera is located lateral of the central longitudinal axis of the tubular enclosure. Viewing from the camera may be continuously unobstructed by the endoscope at the distal end of the camera while the camera is moved relative to the tubular enclosure from the first coupled position to the second coupled position. 
     Another embodiment is an endoscope that includes a camera and a tubular enclosure through which a surgical act may be performed. The camera may be coupled to the tubular enclosure in a first position such that a distal end of the camera is positioned along a central longitudinal axis of the tubular enclosure. Embodiments of the endoscope may also include a means for moving the camera from the first position to a second position wherein the distal end of the camera is not positioned on the central longitudinal axis of the tubular enclosure. Viewing from the camera of some embodiments is continuously unobstructed by the endoscope at the distal end of the camera while the camera is moved relative to the tubular enclosure from the first position to the second position. 
     Still another embodiment is a method of positioning a camera of an endoscope at different perspectives. Method embodiments may include coupling the camera having a distal end to a tubular enclosure having a central longitudinal axis. Method embodiments may also include moving the camera and the tubular enclosure relative to one another to move the distal end of the camera from a first position where the distal end of the camera is positioned on the central longitudinal axis of the tubular enclosure to a second position where the distal end of the camera is not positioned on the central longitudinal axis of the tubular enclosure, without at any time during the movement from the first position to the second position obstructing a view from the distal end of the camera by any portion of the endoscope. 
     Still another embodiment is a method of resecting tissue. Method embodiments may include inserting, into a surgical site within a patient&#39;s body, an endoscope comprising a camera portion and a tubular enclosure associated with the camera, and wherein during the inserting the camera is on a central longitudinal axis of the tubular enclosure. Method embodiments may also include moving the camera lateral of the central longitudinal axis of the tubular enclosure, inserting a resection device through the tubular enclosure, and removing tissue within the surgical site with the resection device while simultaneously viewing the resection by way of the camera. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an embodiment of an endoscope with partial cut-away of some components. 
         FIG.  2    is a perspective view of the embodiment of the endoscope of  FIG.  1    with partial cut-away of some components and with limited visibility of some components. 
         FIG.  3 A  is a side elevation view of the embodiment of the endoscope of  FIG.  1    in a first state. 
         FIG.  3 B  is a side elevation view of the embodiment of the endoscope of  FIG.  1    in a second state. 
         FIG.  3 C  is a side elevation view of the embodiment of the endoscope of  FIG.  1    in a third state. 
         FIG.  3 D  is a cross-sectional view of the embodiment of the endoscope of  FIG.  3 A . 
         FIG.  3 E  is a side elevation view of an embodiment of a camera in accordance with an example embodiment. 
         FIG.  4    is a side elevation view of an embodiment of a camera representing a flexed state and a lateral spring tensioned state. 
         FIG.  4 A  is a side elevation view of an embodiment of an endoscope in a first state. 
         FIG.  4 B  is a side elevation view of the embodiment of the endoscope of  FIG.  4 A  in a second state. 
         FIG.  4 C  is a side elevation view of the embodiment of the endoscope of  FIG.  4 A  in a third state. 
         FIG.  4 D  is a cross-sectional view of the embodiment of the endoscope of  FIG.  4 A . 
         FIG.  5 A  is a side elevation view of an embodiment of an endoscope in a first state. 
         FIG.  5 B  is a side elevation view of the embodiment of the endoscope of  FIG.  5 A  in a second state. 
         FIG.  5 C  is a side elevation view of the embodiment of the endoscope of  FIG.  5 A  in a third state. 
         FIG.  5 D  is a cross-sectional view of the embodiment of the endoscope of  FIG.  5 A . 
         FIG.  6 A  is a side elevation view of an embodiment of an endoscope in a first state. 
         FIG.  6 B  is a side elevation view of the embodiment of the endoscope of  FIG.  6 A  in a second state. 
         FIG.  6 C  is a side elevation view of the embodiment of the endoscope of  FIG.  6 A  in a third state. 
         FIG.  6 D  is a cross-sectional view of the embodiment of the endoscope of  FIG.  6 A . 
     
    
    
     DEFINITIONS 
     Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, different companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection or through an indirect connection via other devices and connections. 
     “Lateral of the central longitudinal axis,” in reference to a camera, shall mean that no portion of a distal end of the camera is intersected by the central longitudinal axis. 
     “On the central longitudinal axis,” in reference to a camera, shall mean that at least some portion of a distal end of a camera is intersected by the central longitudinal axis. 
     “Living hinge” shall mean a hinge defined at a location along a continuous portion of a material, and where the material on either side of the living hinge may be of a different size (measured parallel to an axis of rotation of the hinge) than at the axis of rotation. 
     DETAILED DESCRIPTION 
     Embodiments of an endoscope  300 ,  400 ,  500 ,  600 , respectively are illustrated in  FIGS.  1 - 6 D . Each of the endoscope embodiments  300 ,  400 ,  500 ,  600  includes a camera  310 ,  410 ,  510 ,  610  configured to electrically couple to one or more instruments external to the endoscope  300 ,  400 ,  500 ,  600 . The camera  310 ,  410 ,  510 ,  610  may be coupled to any instrument or device that is useful in relaying or displaying information gathered by the camera  310 ,  410 ,  510 ,  610 . For example and without limitation, the camera  310 ,  410 ,  510 ,  610  may be electrically coupled to a monitor, recorder, computer, memory device, or any other useful device. The camera  310 ,  410 ,  510 ,  610  may be electrically coupled through a wire, such as wire  311 ,  411 ,  511 ,  611 , as illustrated, or may be electrically coupled though a wireless signal by any effective mechanism or of any effective signal type. The illustrated wire  311 ,  411 ,  511 ,  611  is a separate proximally extending member, but in other embodiments may be fully or partially integrated in any proximally extending component of the endoscope  300 ,  400 ,  500 ,  600 . The camera  310 ,  410 ,  510 ,  610  of some embodiments may include a field of view that is between 5 degrees and 180 degrees. Some embodiments may more specifically include a field of view substantially between 80 degrees and 90 degrees. 
     The “field of view” refers to the angle of capture of images (e.g., a picture taken with a fish-eye lens has a wide field of view, while a picture taken with a telephoto lens has a narrow field of view). A related concept is direction of view, where direction of view is a line extending along the center of the field of view. Direction of view can be measured against any suitable reference, such as a longitudinal axis of a component, with the angle between the reference and the direction of view referred to as the “field angle.” With these definitions in mind, the camera  310 ,  410 ,  510 ,  610  of some embodiments may include a direction of view that resides along a longitudinal axis of the camera  310 ,  410 ,  510 ,  610  (i.e., a zero degree field angle relative to the longitudinal axis of the camera). In other embodiments, the direction of view may be skewed from the longitudinal axis of the camera  310 ,  410 ,  510 ,  610  (i.e., a non-zero field angle relative to the longitudinal axis of the camera). A camera with a skewed direction of view may be useful in providing a broader view during insertion. Example insertion configurations are illustrated in  FIGS.  3 A,  4 A,  5 A, and  6 A . With a skewed direction of view, rotation of the endoscope  300 ,  400 ,  500 ,  600  would enable a user to survey a wider area around the end of the endoscope. In other cases, the camera  310 ,  410 ,  510 ,  610  direction of view may be coordinated with the potential displacement of the camera  310 ,  410 ,  510 ,  610 , as shown respectively in  FIGS.  3 B,  3 C,  4 B,  4 C,  5 B,  5 C,  6 B,  6 C , such that when fully or partially displaced, the direction of view is parallel to the central longitudinal axis  350 ,  450 ,  550 ,  650  of a tubular enclosure  320 ,  420 ,  520 ,  620 . One or both of a light and fibre optic light strands may be integrated into any component of or added to the endoscope  300 ,  400 ,  500 ,  600 , as may be useful in providing light for viewing through the camera  310 ,  410 ,  510 ,  610 . 
     Embodiments of an endoscope  300 ,  400 ,  500 ,  600  include the tubular enclosure  320 ,  420 ,  520 ,  620  through which a surgical act may be performed. The camera  310 ,  410 ,  510 ,  610  and the tubular enclosure  320 ,  420 ,  520 ,  620  are movably coupled to one another. In a first coupled position, as shown respectively in  FIGS.  3 A,  4 A,  5 A,  6 A , the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  is positioned on the central longitudinal axis  350 ,  450 ,  550 ,  650  of the tubular enclosure  320 ,  420 ,  520 ,  620 . In a second coupled position, as shown respectively in  FIGS.  3 B and  3 C,  4 B and  4 C,  5 B and  5 C,  6 B and  6 C , the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  is located lateral of the central longitudinal axis  350 ,  450 ,  550 ,  650  of the tubular enclosure  320 ,  420 ,  520 ,  620 . As used herein, the term “lateral of the central longitudinal axis” means that no portion of a distal end of a camera is intersected by the central longitudinal axis. The term “on the central longitudinal axis” means that at least some portion of a distal end of a camera is intersected by the central longitudinal axis. The distal end of a camera may include not only the very far distal tip of a camera but also portions of the camera near the very far distal tip. In the embodiments illustrated, viewing from the camera  310 ,  410 ,  510 ,  610  is continuously unobstructed by the endoscope  300 ,  400 ,  500 ,  600  at the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  while the camera  310 ,  410 ,  510 ,  610  is moved relative to the tubular enclosure  320 ,  420 ,  520 ,  620  from the first coupled position to the second coupled position. Stated another way, in some embodiments, no portion of the endoscope  300 ,  400 ,  500 ,  600  is positioned distally of the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  while the camera  310 ,  410 ,  510 ,  610  is moved relative to the tubular enclosure  320 ,  420 ,  520 ,  620  from the first coupled position to the second coupled position. Stated yet another way, in some embodiments, unobstructed viewing is a result of a structure where the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  is the most distal element of the endoscope  300 ,  400 ,  500 ,  600 . More specifically, the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  may be the most distal element of the endoscope  300 ,  400 ,  500 ,  600  during movement from the first coupled position to the second coupled position. 
     As illustrated in  FIGS.  1 - 3 E , the endoscope  300  also includes a sheath  330  in which the camera  310  and the tubular enclosure  320  are sized to fit. The tubular enclosure  320  shown is a cannula capable of longitudinally sliding relative to the sheath  330  and relative to the camera  310 . The tubular enclosure  320  is open at both its proximal and distal ends and includes solid walls. However, in other embodiments proximal and distal ends may be partially closed or closable and the walls may not extend completely around the perimeter of the tubular enclosure at some or all longitudinal distances along the tubular enclosure. Some embodiments of a tubular enclosure may include a distal end that is rounded or chamfered to lessen stresses at points of contact with other components that are distal of the tubular enclosure when the endoscope is change between states. To the extent that reference is made to a central longitudinal axis  350  extending from a tubular enclosure that is curved along all or part of its length, the central longitudinal axis  350  may be considered to extend substantially normally from a distal end of the tubular enclosure. 
     The camera  310  comprises camera body  315  that defines a distal end  312  of the camera  310 . In example embodiments the camera body  315  proximate to the distal end  312  has a circular cross section, and thus a circumferential length that fully encircles the central longitudinal axis  350  (when the camera  310  is in the configuration shown in  FIG.  3 A ). The proximally extending member  316  in the example embodiments is contiguous with the camera body  315 , and in the example shown the circumferential length of the proximally extending member  316  does not fully encircle the central longitudinal axis  350  (as best shown in the cross-sectional view of  FIG.  3 D ). Measured as angle about (and perpendicular to) the central longitudinal axis  350 , the proximally extending member  316  spans a non-zero value less than 180 radial degrees, in some cases a non-zero value less than 90 radial degrees, and in other cases the proximally extending member  316  spans about 70 radial degrees. 
     The camera  310  depicted is also capable of longitudinally sliding relative to the sheath  330 . For example, the endoscope  300  may be introduced into tissue with the camera  310  fully or substantially retracted within the sheath  330 , as shown in  FIG.  3 A . In  FIGS.  3 B and  3 C , the camera  310  is shown following longitudinal sliding relative to the sheath  330  to enable the camera  310  to be in a position to be further acted on by the tubular enclosure  320 . The camera  310  shown includes the camera body  315  with the distal end  312  and a proximally extending member  316  that is coupled to the camera body  315 . In some embodiments, one or both of the proximally extending member  316  and the camera body  315  may include along at least part of their lengths a lateral spring force configured to bias one or both of the proximally extending member  316  and the camera body  315  into a curved shape. For example, lateral spring forces may exist in the components that tend to push the distal end  312  away from the central longitudinal axis  350  of the tubular enclosure  320 . In the alternative, lateral spring forces may exist in the components that tend to push the distal end  312  toward the central longitudinal axis  350  of the tubular enclosure  320  so that, in the example shown in the second and third states of  FIGS.  3 B and  3 C  a resistive force is maintained by the camera  310  against the tubular enclosure  320  as the tubular enclosure  320  is advanced distally. Lateral spring forces of some embodiments may exist along the entire lengths of the proximally extending member  316  and the camera body  315  or may be limited to specific segments of either. As shown in  FIGS.  2 ,  3 B, and  3 C , the camera  310  may include a proximally directed surface  317  shaped so that when the proximally directed surface  317  is contacted by the tubular enclosure  320 , the tubular enclosure  320  moves the camera  310  from the first coupled position toward the second coupled position. As shown in the example system, the proximally directed surface  317  is a curved surface. The radius of curvature R ( FIG.  3 E ) may be at least twice the outside diameter (OD) of the camera body  315 , in some cases at least four times the OD of the camera body  315 , and in a specific case the radius of curvature is 5 times the OD of the camera body. 
     In some embodiments, the proximally directed surface may include compound curved surfaces that interact with a tubular enclosure to control rates and amounts of deflections of the camera  310  in response to movements of the tubular enclosure  320 . In some embodiments, a proximally directed surface may have one or more planar surfaces with at least one surface being in a different plane from surfaces of the tubular enclosure  320  configured to contact the proximally directed surface. 
     The movable coupling between the camera  310  and the tubular enclosure  320  includes a mechanism for longitudinal sliding between the camera  310  and the tubular enclosure  320 , as illustrated in the changes of relative state illustrated in  FIGS.  3 A- 3 C . In addition, in the illustrated embodiment, the movable coupling between the camera  310  and the tubular enclosure  320  includes a mechanism for movement substantially about an axis  360  ( FIG.  3 C ) perpendicular to the central longitudinal axis  350  of the tubular enclosure  320 . The illustrated embodiment shows a living hinge between the camera  310  and the tubular enclosure  320  to the extent that the living hinge at the axis  360  is within a portion of the camera  310  between the camera body  315  and the proximally extending member  316 , and the proximally extending member  316  is not rotationally movable relative to the tubular enclosure  320 . In other embodiments, the illustrated living hinge may be replaced or supplemented by one or more pinned hinges. 
       FIGS.  3 A and  3 D  also show an example direction of view. In particular,  FIG.  3 A  shows the example camera has a longitudinal axis that is coaxial with the central longitudinal axis  350 , and the direction of view  302  is skewed from the central longitudinal axis  350  thus forming a field angle α. Thus, during insertion of the endoscope  300  in the configuration of  FIG.  3 A , the direction of view  302  is not parallel to the central longitudinal axis  350 . However, the field angle α is selected such that when the camera  310  is fully extended and in the second coupled position ( FIG.  3 C ), the direction of view  302  is substantially parallel to the central longitudinal axis  350  (and the field angle α is measured with respect to the longitudinal axis  303  of the camera  315 . The field angle α, and thus the direction of view  302 , may be implemented by a prism (not specifically shown) associated with the camera  310 . The same field angles and directions of view may be implemented in any of the embodiments discussed herein. 
     Referring to  FIG.  3 B , in some example embodiments the sheath  330  may include a window or cut-out  304  (shown in dashed lines) to enable the camera  310  to move transversely (e.g., to the orientation shown in  FIG.  3 C ) without requiring as much relative movement of the sheath  330  on the one hand, and the camera  310  and tubular enclosure  320  on the other hand. 
     As illustrated in  FIGS.  4 - 4 D , the tubular enclosure  420  of endoscope  400  is a sheath in which the camera  410  is sized to fit. The camera  410  shown is capable of longitudinally sliding relative to the tubular enclosure  420 . The tubular enclosure  420  is open at both its proximal and distal ends and includes solid walls. However, in other embodiments proximal and distal ends may be partially closed or closable and the walls may not extend completely around the perimeter of the tubular enclosure at some or all longitudinal distances along the tubular enclosure. Some embodiments of a tubular enclosure may include a distal end that is rounded or chamfered. To the extent that reference is made to a central longitudinal axis  450  extending from a tubular enclosure that is curved along all or part of its length, the central longitudinal axis  450  may be considered to extend substantially normally from a distal end of the tubular enclosure. 
     The camera  410  shown includes a camera body  415  with the distal end  412  and a proximally extending member  416  that is coupled to the camera body  415 . In some embodiments, one or both of the proximally extending member  416  and the camera body  415  may include along at least part of their lengths a lateral spring force configured to bias one or both of the proximally extending member  416  and the camera body  415  into a curved shape. The proximally extending member  416  is shown in  FIG.  4    with a lateral spring force. The dashed lines show the proximally extending member  416  aligning with the longitudinal axis of the camera body and represent a configuration where the proximally extending member  416  would be under a lateral spring force. The solid lines for the proximally extending member  416  represent a state where the lateral spring force is released. In the embodiment depicted, the lateral spring forces induced by inserting the camera  410  into the tubular enclosure  420  tend to push the distal end  412  away from the central longitudinal axis  450  of the tubular enclosure  420 , as illustrated in  FIGS.  4 B and  4 C . Lateral spring forces may be designed into the entire lengths of the proximally extending member  416  and the camera body  415  or may be limited to specific segments of either. The endoscope  400  may be introduced into tissue with the camera  410  fully or substantially retracted within the tubular enclosure  420 , as shown in  FIG.  4 A . In  FIGS.  4 B and  4 C , the camera  410  is shown following longitudinal sliding relative to the tubular enclosure  420 . As the camera  410  is moved beyond a distal end of the tubular enclosure  420 , the lateral spring forces in the proximally extending member  416  are released and push the distal end  412  away from the central longitudinal axis  450  of the tubular enclosure  420 . This movement results in the distal end  412  of the camera  410  being moved from the first coupled position, represented in  FIG.  4 A , to the second coupled position, represented in both of  FIGS.  4 B and  4 C . 
     The endoscope  400  illustrated does not require an additional component to be pressed against the camera  410  to move the distal end  412  of the camera  410  away from the central longitudinal axis  450  due to the orientation and degree of later spring force induced in the components of the camera  410 . However, an additional cannula may be used with the endoscope  400  to provide a smoother working channel or to positively move portions of the camera  410  out of a working area within the tubular enclosure  420 . In a situation where an additional cannula were to be used, the camera  410  may include a proximally directed surface  417  shaped so that when the proximally directed surface  417  is contacted by the additional cannula similarly to the interactions of the tubular enclosure  320  and the proximally directed surface  317  noted above. 
     The movable coupling between the camera  410  and the tubular enclosure  420  includes a mechanism for longitudinal sliding between the camera  410  and the tubular enclosure  420 , as illustrated in the changes of relative state illustrated in  FIGS.  4 A- 4 C . In addition, in the illustrated embodiment, the movable coupling between the camera  410  and the tubular enclosure  420  includes a mechanism for movement substantially about an axis  460  ( FIG.  4 C ) perpendicularly to the central longitudinal axis  450  of the tubular enclosure  420 . The illustrated embodiment shows a living hinge between the camera  410  and the tubular enclosure  420  to the extent that the living hinge at the axis  460  is within a portion of the camera  410  between the camera body  415  and the proximally extending member  416 , and the proximally extending member  416  is not rotationally movable relative to the tubular enclosure  420 . In other embodiments, the illustrated living hinge may be replaced or supplemented by one or more pinned hinges. The relative circumferential lengths of the proximally extending member  416  and the camera body  415  may be as described above in reference to the proximally extending member  316  and the camera body  315 .  FIG.  4 D  shows the proximally extending member  416  within the tubular enclosure  420 , along with the wire  411 . 
     As illustrated in  FIGS.  5 - 5 D , the tubular enclosure  520  is a cannula capable of longitudinally sliding relative to the camera  510 . In the embodiment shown, the tubular enclosure  520  and the camera  510  are movably coupled to one another such that the tubular enclosure  520  and the camera  510  will not move laterally away from one another at locations where the tubular enclosure  520  and the camera are coupled. In particular, in this embodiment, the tubular enclosure  520  includes a dovetail spline  522  and the camera  510  includes a dovetail notch  524  ( FIG.  5 D ). The longitudinal axis of the dovetail joint formed between the dovetail spline  522  and the dovetail notch  524  is substantially parallel with the central longitudinal axis  550  of the tubular enclosure  520 . In some embodiments having a dovetail joint, a dovetail spline may be on a camera and a dovetail notch may be on a tubular enclosure. Other similar embodiments may achieve a longitudinally sliding but non-moving lateral coupling by any effective mechanism, including mechanisms that do not use of a dovetail joint. 
     The tubular enclosure  520  depicted is open at both its proximal and distal ends and includes solid walls. However, in other embodiments proximal and distal ends may be partially closed or closable and the walls may not extend completely around the perimeter of the tubular enclosure at some or all longitudinal distances along the tubular enclosure. Some embodiments of a tubular enclosure may include a rounded distal surface or a chamfered distal surface  527  ( FIG.  5 C ) to lessen stresses at points of contact with other components that are distal of the tubular enclosure when the endoscope is change between states. To the extent that reference is made to a central longitudinal axis  550  extending from a tubular enclosure that is curved along all or part of its length, the central longitudinal axis  550  may be considered to extend substantially normally from a distal end of the tubular enclosure. 
     The camera  510  shown includes a camera body  515  with the distal end  512  and a proximally extending member  516  that is coupled to the camera body  515 . In some embodiments, one or both of the proximally extending member  516  and the camera body  515  may include along at least part of their lengths a lateral spring force configured to bias one or both of the proximally extending member  516  and the camera body  515  into a curved shape. For example, lateral spring forces may exist in the components that tend to push the distal end  512  away from the central longitudinal axis  550  of the tubular enclosure  520 . In the alternative, lateral spring forces may exist in the components that tend to push the distal end  512  toward the central longitudinal axis  550  of the tubular enclosure  520 . Lateral spring forces of some embodiments may exist along the entire lengths of the proximally extending member  516  and the camera body  515  or may be limited to specific segments of either. As shown in  FIGS.  5 A- 5 C , the camera  510  may include a proximally directed surface  517  shaped so that when the proximally directed surface  517  is contacted by the tubular enclosure  520 , the tubular enclosure  520  moves the camera  510  from the first coupled position toward the second coupled position. As shown in this example, the proximally directed surface  517  is a curved surface, and the radius of curvature may be as described in reference to  FIG.  3 E  above. In some embodiments, a proximally directed surface may include compound curved surfaces that interact with a tubular enclosure to control rates and amounts of deflections of the camera  510  in response to movements of the tubular enclosure  520 . In some embodiments, a proximally directed surface may have one or more planar surfaces with at least one surface being in a different plane from surfaces of the tubular enclosure  520  configured to contact the proximally directed surface. 
     The movable coupling between the camera  510  and the tubular enclosure  520  includes a mechanism for longitudinal sliding between the camera  510  and the tubular enclosure  520 , as illustrated in the changes of relative state illustrated in  FIGS.  5 A- 5 C . In addition, in the illustrated embodiment, the movable coupling between the camera  510  and the tubular enclosure  520  includes a mechanism for movement substantially about an axis  560  ( FIGS.  5 A- 5 C ) perpendicular to the central longitudinal axis  550  of the tubular enclosure  520 . The illustrated embodiment shows a living hinge between the camera  510  and the tubular enclosure  520  to the extent that the living hinge at the axis  560  is within a portion of the camera  510  between the camera body  515  and the proximally extending member  516 , and the proximally extending member  516  is not rotationally movable relative to the tubular enclosure  520 . In other embodiments, the illustrated living hinge may be replaced or supplemented by one or more pinned hinges. 
     As illustrated in  FIGS.  6 A- 6 D , the endoscope  600  also includes a sheath  630  to which the camera  610  is coupled at a distal end of the sheath  630 . The tubular enclosure  620  is sized to fit within the sheath  630 . The tubular enclosure  620  shown is a cannula capable of longitudinally sliding relative to the sheath  630  and relative to the camera  610 . The tubular enclosure  620  is open at both its proximal and distal ends and includes solid walls. However, in other embodiments proximal and distal ends may be partially closed or closable and the walls may not extend completely around the perimeter of the tubular enclosure at some or all longitudinal distances along the tubular enclosure. Some embodiments of a tubular enclosure may include a distal end that is rounded or chamfered to lessen stresses at points of contact with other components that are distal of the tubular enclosure when the endoscope is change between states. To the extent that reference is made to a central longitudinal axis  650  extending from a tubular enclosure that is curved along all or part of its length, the central longitudinal axis  650  may be considered to extend substantially normally from a distal end of the tubular enclosure. 
     The camera  610  depicted is not capable of longitudinally sliding relative to the sheath  630  but may be rotated relative to the sheath  630  and the tubular enclosure  620 , as discussed in more detail below. The endoscope  600  may be introduced into tissue with a longitudinal axis of the camera  610  substantially parallel with the central longitudinal axis  650  of the tubular enclosure  620 . In the embodiment shown, the rotational coupling between the sheath  630  and the camera  610  may be stiff enough to resist rotation during introduction into tissue, as illustrated by the position shown in  FIG.  6 A . In  FIGS.  6 B and  6 C , the camera  610  is shown following longitudinal sliding of the tubular enclosure  620  relative to the sheath  630 . The camera  610  shown includes a camera body  615  with the distal end  612  and a relatively short proximally extending member  616  that is coupled to the camera body  615 . In some embodiments, one or both of the proximally extending member  616  and the camera body  615  may include along at least part of their lengths a lateral spring force configured to bias one or both of the proximally extending member  616  and the camera body  615  into a curved shape. For example, lateral spring forces may exist in the components that tend to push the distal end  612  toward the central longitudinal axis  650  of the tubular enclosure  620 . Lateral spring forces of some embodiments may exist along the entire lengths of the proximally extending member  616  and the camera body  615  or may be limited to specific segments of either. As shown in  FIGS.  6 A- 6 C , the camera  610  may include a proximally directed surface  617  shaped so that when the proximally directed surface  617  is contacted by the tubular enclosure  620 , the tubular enclosure  620  moves the camera  610  from the first coupled position toward the second coupled position. As shown in this example, the proximally directed surface  617  is a curved surface, and may have a radius of curvature as discussed above in reference to  FIG.  3 E . In some embodiments, a proximally directed surface may include compound curved surfaces that interact with a tubular enclosure to control rates and amounts of deflections of the camera  610  in response to movements of the tubular enclosure  620 . In some embodiments, a proximally directed surface may have one or more planar surfaces with at least one surface being in a different plane from surfaces of the tubular enclosure  620  configured to contact the proximally directed surface. 
     A direct but movable coupling exists between the camera  610  and the sheath  630  about an axis  660  ( FIGS.  6 B and  6 C ) transverse to the central longitudinal axis  650  of the tubular enclosure  620  in the illustrated embodiment. The movable coupling between the camera  610  and the tubular enclosure  620  includes a mechanism for longitudinal sliding between the camera  610  and the tubular enclosure  620 , as illustrated in the changes of relative state illustrated in  FIGS.  6 A- 6 C . In addition, in the illustrated embodiment, the movable coupling between the camera  610  and the tubular enclosure  620  includes a mechanism for movement substantially about the axis  660  ( FIGS.  6 B and  6 C ) transverse to the central longitudinal axis  650  of the tubular enclosure  620 . The illustrated embodiment shows a living hinge between the camera  610  and the tubular enclosure  620  to the extent that the living hinge at the axis  660  is within a portion of the camera  610  between the camera body  615  and the proximally extending member  616 , and the proximally extending member  616  is not rotationally movable relative to the tubular enclosure  620 . In other embodiments, the illustrated living hinge may be replaced or supplemented by one or more pinned hinges. 
     Each of the illustrated endoscope embodiments  300 ,  400 ,  500 ,  600  includes the camera  310 ,  410 ,  510 ,  610  and the tubular enclosure  320 ,  420 ,  520 ,  620  through which a surgical act may be performed. The camera  310 ,  410 ,  510 ,  610  in a first position ( FIGS.  3 A,  4 A,  5 A,  6 A , respectively) is coupled to the tubular enclosure  320 ,  420 ,  520 ,  620  such that the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  is positioned on the central longitudinal axis  350 ,  450 ,  550 ,  650  of the tubular enclosure  320 ,  420 ,  520 ,  620 . Each of the illustrated endoscope embodiments  300 ,  400 ,  500 ,  600  also includes means for moving the camera  310 ,  410 ,  510 ,  610  from the first position to a second position wherein the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  is not positioned on the central longitudinal axis  350 ,  450 ,  550 ,  650  of the tubular enclosure  320 ,  420 ,  520 ,  620 . In each of the illustrated embodiments, viewing from the camera  310 ,  410 ,  510 ,  610  is continuously unobstructed by the endoscope  300 ,  400 ,  500 ,  600  at the distal end  312 ,  412 ,  512 ,  612  of the camera  310 ,  410 ,  510 ,  610  when the camera  310 ,  410 ,  510 ,  610  is moved relative to the tubular enclosure  320 ,  420 ,  520 ,  620  from the first position to the second position. 
     A method embodiment is a method of positioning a camera at different perspectives. In the illustrated embodiments, the camera is a component of an endoscope. For illustrative purposes, and without limiting the scope of the method disclosed, the four endoscopes  300 ,  400 ,  500 ,  600  disclosed herein will be referenced in describing the method. The method may include coupling a camera  310 ,  410 ,  510 ,  610  having a distal end  312 ,  412 ,  512 ,  612  to a tubular enclosure  320 ,  420 ,  520 ,  620 . The mechanisms for coupling are different for each of the endoscopes  300 ,  400 ,  500 ,  600 , but operation of each mechanism is within the method disclosed. The endoscope  300  includes the camera  310  that is coupled with the tubular enclosure  320  by a proximally extending member  316  of the camera  310  being captured between the tubular enclosure  320  and the sheath  330  at each state of movement illustrated in  FIGS.  3 A- 3 C . As shown in  FIGS.  1 - 3 A , the distal end  312  of the camera  310  is positioned on the central longitudinal axis  350  of the tubular enclosure  320  in a first state. Movement of the camera  310  and the tubular enclosure  320  relative to one another, as illustrated in the state change between  FIG.  3 A  and  FIG.  3 B , causes movement to a second position where the distal end  312  of the camera  310  is not positioned on the central longitudinal axis  350  of the tubular enclosure  320 . Movement between the tubular enclosure  320  and the camera  310  in this embodiment also includes a distal end of the tubular enclosure  320  pushing against a proximally directed surface  317  of the camera  310  to flex the distal end  312  of the camera  310  away from the central longitudinal axis  350 . In this embodiment, the moving act is carried out without at any time obstructing a view from the distal end  312  of the camera  310  by any portion of the endoscope  300 . This unobstructed view may be useful when an intermediate perspective for positioning the distal end  312  of the camera  310  is needed. In other words, a user may want the perspective of either the state illustrated in  FIG.  3 B  or  FIG.  3 C , or any intermediate perspective between the states of  FIG.  3 A  and  FIG.  3 C , without a portion of the endoscope  300  blocking a view of the camera  310  when at or between any perspective. 
     The endoscope  400  includes the camera  410  that is coupled with the tubular enclosure  420  by placing the camera  410  within the tubular enclosure  420 . As depicted in  FIG.  4   , the proximally extending member  416  of the camera  410  includes a lateral spring force. When placed in the tubular enclosure  420  and then moved from the distal end of the tubular enclosure  420 , this lateral spring force urges the distal end  412  of the camera  410  from the position shown in  FIG.  4 A  to the position shown in  FIG.  4 B . The distal end  412  of the camera  410  is positioned on the central longitudinal axis  450  of the tubular enclosure  420  in a first state in  FIG.  4 A . Movement of the camera  410  and the tubular enclosure  420  relative to one another, as illustrated in the state change between  FIG.  4 A  and  FIG.  4 B , causes movement to a second position where the distal end  412  of the camera  410  is not positioned on the central longitudinal axis  450  of the tubular enclosure  420 . As noted, lateral movement of the distal end  412  of the camera  410  in this embodiment is urged by a lateral spring force in the proximally extending member  416 . In this embodiment, the moving act is carried out without at any time obstructing a view from the distal end  412  of the camera  410  by any portion of the endoscope  400 . This unobstructed view may be useful when an intermediate perspective for positioning the distal end  412  of the camera  410  is needed. In other words, a user may want the perspective of either the state illustrated in  FIG.  4 B  or  FIG.  4 C , or any intermediate perspective between the states of  FIG.  4 A  and  FIG.  4 C , without a portion of the endoscope  300  blocking a view of the camera  310  when at or between any perspective. 
     The endoscope  500  includes the camera  510  that is coupled with the tubular enclosure  520  by coupling the camera  510  along an outer portion of the tubular enclosure  520 . As most clearly illustrated in  FIG.  5 D , the illustrated embodiment includes a dovetail joint between the camera  510  and the tubular enclosure  520 . The dovetail notch  524  extends substantially along the length of the proximally extending member  516  of the camera  510 , but not into the camera body  515 . The dovetail spline  522  on the tubular enclosure  520  cooperates with the dovetail notch  524  to provide for movement of the camera  510  and the tubular enclosure  520  relative to each other parallel with the central longitudinal axis  550  without allowing movement of the camera  510  laterally away from the tubular enclosure  520  where the tubular enclosure  520  and the camera  510  are coupled, which is along the dovetail notch  524  in this embodiment. As shown in  FIG.  5 A , the distal end  512  of the camera  510  is positioned on the central longitudinal axis  550  of the tubular enclosure  520  in a first state. Movement of the camera  510  and the tubular enclosure  520  relative to one another, as illustrated in the state change between  FIG.  5 A  and  FIG.  5 B , causes movement to a second position where the distal end  512  of the camera  510  is not positioned on the central longitudinal axis  550  of the tubular enclosure  520 . Movement between the tubular enclosure  520  and the camera  510  in this embodiment also includes a chamfered distal end  527  of the tubular enclosure  520  pushing against a proximally directed surface  517  of the camera  510  to flex the distal end  512  of the camera  510  away from the central longitudinal axis  550 . In this embodiment, the moving act is carried out without at any time obstructing a view from the distal end  512  of the camera  510  by any portion of the endoscope  500 . This unobstructed view may be useful when an intermediate perspective for positioning the distal end  512  of the camera  510  is needed. In other words, a user may want the perspective of either the state illustrated in  FIG.  5 B  or  FIG.  5 C , or any intermediate perspective between the states of FIG.  5 A and  FIG.  5 C , without a portion of the endoscope  500  blocking a view of the camera  510  when at or between any perspective. 
     The endoscope  600  includes the camera  610  that is coupled with the tubular enclosure  620  by a proximally extending member  616  of the camera  610  being coupled to the sheath  630  and the tubular enclosure  620  is captured within the sheath  630 . As shown in  FIG.  6 A , the distal end  612  of the camera  610  is positioned on the central longitudinal axis  650  of the tubular enclosure  620  in a first state. Movement of the camera  610  and the tubular enclosure  620  relative to one another, as illustrated in the state change between  FIG.  6 A  and  FIG.  6 B , causes movement to a second position where the distal end  612  of the camera  610  is not positioned on the central longitudinal axis  650  of the tubular enclosure  620 . Movement between the tubular enclosure  620  and the camera  610  in this embodiment also includes a distal end of the tubular enclosure  620  pushing against a proximally directed surface  617  of the camera  610  to flex the distal end  612  of the camera  610  away from the central longitudinal axis  650 . In this embodiment, the moving act is carried out without at any time obstructing a view from the distal end  612  of the camera  610  by any portion of the endoscope  600 . This unobstructed view may be useful when an intermediate perspective for positioning the distal end  612  of the camera  610  is needed. In other words, a user may want the perspective of either the state illustrated in  FIG.  6 B  or  FIG.  6 C , or any intermediate perspective between the states of  FIG.  6 A  and  FIG.  6 C , without a portion of the endoscope  600  blocking a view of the camera  610  when at or between any perspective. 
     Various embodiments of an endoscope wholly or its components individually may be made from any biocompatible material. For example and without limitation, biocompatible materials may include in whole or in part: non-reinforced polymers, reinforced polymers, thermoplastics, metals, ceramics, adhesives, reinforced adhesives, and combinations of these materials. Reinforcing of polymers may be accomplished with carbon, metal, or glass or any other effective material. Examples of biocompatible polymer materials include polyamide base resins, polyethylene, Ultra High Molecular Weight (UHMW) polyethylene, low density polyethylene, polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polymeric hydroxyethylmethacrylate (PHEMA), and polyurethane, any of which may be reinforced. Example biocompatible metals include stainless steel and other steel alloys, cobalt chrome alloys, zirconium, oxidized zirconium, tantalum, titanium, titanium alloys, titanium-nickel alloys such as Nitinol and other superelastic or shape-memory metal alloys. 
     Terms such as proximal, distal, lateral, near, far, away, small, and the like have been used relatively herein. However, such terms are not limited to specific coordinate orientations, distances, or sizes, but are used to describe relative positions or sizes referencing particular embodiments. Such terms are not generally limiting to the scope of the claims made herein. Any embodiment or feature of any section, portion, or any other component shown or particularly described in relation to various embodiments of similar sections, portions, or components herein may be interchangeably applied to any other similar embodiment or feature shown or described herein. 
     While embodiments of the invention have been illustrated and described in detail in the disclosure, the disclosure is to be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the invention are to be considered within the scope of the disclosure.