CONCENTRIC TUBE APPARATUS FOR MINIMALLY INVASIVE SURGERY

TECHNICAL FIELD

[0001] The present invention relates to surgical devices and associated methods for performing surgery. More particularly, the present invention relates to tools and methods for minimally invasive surgery using concentric tube assemblies. BACKGROUND ART

[0002] Minimally invasive surgery using electromechanical robots is a developing field of medicine. Conventional devices for performing minimally invasive surgery, such as endoscopes and resectoscopes, generally include a distal tip that is inserted through an incision or a natural orifice in a patient’s body. The distal tip includes an optical lens which allows a surgeon to see a field of view proximate to the distal tip when placed inside the body. The endoscope will typically have a camera attached to the lens to display the field of view on an operating room monitor. In some applications the endoscope includes a camera installed on the distal tip of the endoscope. The device also includes a narrow working channel extending through the device. One or more elongated surgical tools may be inserted through the working channel. A tool such as a cutting device, a basket or a laser optic may be included on the surgical tool. The distal end of the surgical tool protrudes from the distal tip of the device, thereby allowing the surgeon to visually observe operation of the tool inside the patient’s body during an operation.

[0003] Conventional surgical tools for use through the narrow working channel of an endoscope or resectoscope are generally limited in size, and are particularly limited in the range of motion and freedom of manipulation of the tool ends extending from the distal end of the endoscope or resectoscope. Curved channels within the endoscope or resectoscope have been proposed as a possible solution to achieve a better range of motion and better ability to manipulate tools in the workspace. However, providing curved channels for passage of surgical tools inside the narrow confines of an endoscope or resectoscope present additional challenges. For example, curved concentric tubes tend to align with the plane of curvature of the channel in which the concentric tube is housed. As a result, a curved tube of a surgical tool positioned inside a curved channel on an endoscope may provide improved range of motion when extended from the distal end of the channel, but such a configuration does not provide an optimal solution when manipulation outside of the plane of curvature of the channel is desired.

[0004] Over the past few decades, it has become increasingly clear that entering the body in the most minimally invasive way possible during surgery provides tremendous patient benefit. Minimally invasive surgery is a general term used to describe any surgical procedure that enters the body without large, open incisions. Conventional devices for performing minimally invasive surgery, such as endoscopes and resectoscopes, are generally rigid and include a distal tip that is inserted through an incision in a patient’s body or a natural orifice in a patient’s body. The distal tip includes an optical lens which allows a surgeon to see a field of view proximate to the distal tip when placed inside the body. The endoscope will typically have a camera attached to it to display the field of view on an operating room monitor. In some applications the endoscope includes a camera installed on the distal tip of the endoscope. The device also includes a working channel extending through the device. One or more elongated surgical tools may be inserted through the working channel. A tool such as a cutting device, a basket or a laser optic may be included on the surgical tool. The distal end of the surgical tool protrudes from the distal tip of the device, thereby allowing the surgeon to visually observe operation of the tool inside the patient’s body during an operation.

[0005] Minimally invasive surgery includes laparoscopic surgery, which uses a tube to deliver visualization (i.e. an endoscope) and view the surgical field and long, rigid instruments that pass through small ports in the body. In conventional laparoscopic surgery, the endoscope is usually used only for visualization of the surgical field and does not have tools passing through it. The tools are pivoted outside of the body and through the incision port to provide instrument manipulation at the surgical site. The tool manipulation in laparoscopic surgery is created by pivoting long, rigid shafts through ports in the body. For surgery in the insufflated abdomen, chest cavity, pelvis or any other anatomical working volume with sufficient space, this concept often provides an excellent minimally invasive solution for delivering instrument manipulation. However, when the surgical site is down a long, narrow channel, the ability to pivot these long, rigid shafts diminishes. The tool’s manipulation ability drops off sharply as access channels become longer and/or narrower.

[0006] Minimally invasive surgery also includes endoscopic surgery. While laparoscopic surgery uses endoscopes to provide visualization, endoscopic surgery differs in that the surgical instruments are passed through a working channel of the endoscope tube itself. Some examples of surgical instruments that can be used during endoscopic surgery are scissors, forceps, laser fibers, and monopolar/bipolar cautery. There are both rigid and flexible endoscopes — rigid endoscopes being used in surgeries where a straight, linear path can be taken from the outside of the body to the surgical site, and flexible endoscopes being used where winding through curving anatomy is required. Rigid endoscopes are currently used in almost every area of surgery, including but not limited to neurologic, thoracic, orthopedic, urologic and gynecologic procedures. While rigid endoscopy is currently used in surgeries all over the body, it is not without drawbacks. Tools that operate through the working channel of rigid endoscopes are similar to laparoscopic tools in that they are normally straight, rigid tools. Generally, these tools are also limited to two degrees-of-freedom motion relative to the endoscope: they can insert/retract and rotate axially. Sometimes, the surgeon may have the ability to pivot/tilt the endoscope outside of the body, which makes things particularly challenging, as whenever the endoscope moves, the field of view of the endoscope moves along with it. Also, the surgeon can only get one instrument at a time to the surgical site the vast majority of the time due to the size constraints of the working channel of the endoscope — effectively eliminating the ability for two-handed bimanual tasks. This limitation to a single tool at a time, the constantly changing field of view, limited degrees of freedom, and lack of instrument dexterity at the tip of the endoscope make endoscopic surgery a particularly challenging type of minimally invasive surgery.

[0007] Because they are particularly skilled with precision, spatial reasoning, and dexterity, electromechanical surgical robots have great potential to aid in surgical instrument manipulation and is a rapidly developing field of medicine. Surgical robots have gained widespread adoption throughout the world and have been utilized in hundreds of thousands of procedures. The majority of surgical robotic systems designed thus far that aid in instrument manipulation can be generally categorized into pivoted and flexible tools. Pivoted, laparoscopic-like systems such as the widely used da Vinci Xi robot, made by Intuitive Surgical, Inc., gain instrument manipulation in the same way that laparoscopic tools do: by tilting through a port in the body. For surgical applications where tilting or pivoting of the tools is not possible outside of the body, several groups in the research community have been developing robotic systems based on flexible elements. These systems are often referred to as continuum robots, or a continuously bending, robot with an elastic structure. There also exist concentric tube manipulators, which are a class of miniature, needle-sized continuum robot composed of concentric, elastic tubes. Concentric tube robots appear promising in many kinds of minimally invasive surgical interventions that require small diameter robots with articulation inside the body. Examples include surgery in the eye, ear, sinuses, lungs, prostate, brain, and other areas. In most of these applications, higher curvature is generally desirable to enable the robot to turn “tighter corners” inside the human body and work dexterously at the surgical site. In the context of endoscopic surgery, the precurvatures of the concentric tubes determine how closely the manipulators can work to the tip of the endoscope, which is very important during endoscopic surgery.

[0008] With traditional endoscopic procedures, surgeons typically hold the endoscope in one hand and the endoscopic instrument in the other, making it generally not possible for the surgeon to simultaneously manipulate two instruments. Due to the human error aspect, whenever the surgeon needs to swap one endoscopic instrument out for another, it can result in awkward and potentially dangerous endoscope movements. Surgeons often, however, need the ability to accurately and simultaneously manipulate two instruments in certain situations — especially when trying to grasp, manipulate, and cut material precisely. Even where endoscopes can accommodate more than one tool simultaneously, the tools can only be oriented straight out and parallel to one another, which prohibits truly collaborative work between the tools. Surgeons can greatly benefit from the increased precision, dexterity, and vision that robotic surgery systems offer, but such conventional systems are limited in their manipulability.

[0009] Another problem with conventional surgical robots is that parallel tube configurations extending from endoscopic devices do not provide triangulation of the tools in a workspace in the field of view near the tip of the endoscope. Additionally, such conventional configurations include tubes that extend generally parallel along a longitudinal axis, which makes it nearly impossible to apply off-axis forces for pushing or pulling tissue from side to side. Such configurations place also place a nominal interaction point where first and second tools interact significantly beyond the field of view and effective workspace at the tip of the endoscope. As such, it is difficult to manipulate tissue using two endoscopic tools working together using conventional devices.

[00010] What is needed, then, are improvements in devices and methods for performing robotic surgery, and specifically for controlling and manipulating first and second tools in cooperation, in a field of view near the tip of an endoscopic device. DISCLOSURE OF INVENTION

[0001] This Brief Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0002] A device for performing minimally invasive surgery includes a concentric tube assembly with a distal tip configured for insertion into a patient’s body through a small incision or orifice. The tube assembly includes a channel and a guide tube housed within the channel. The guide tube is configured to translate axially and to rotate relative to the channel. An inner tube is positioned inside the guide tube and is also independently moveable in axial translation and rotation relative to the guide tube. The guide tube is operable to steer the distal end of the inner tube to a desired location in a tissue workspace defined at the end of the tube assembly.

[0003] The guide tube includes a pre-shaped, highly-curved distal end. The channel also has a curved shape near its distal opening. The curved channel and highly-curved guide tube work together to form an elbow-like configuration, allowing the guide tube to enter a tissue workspace at an angle relative to a centerline axis. Such an angled entry into the workspace provides superior triangulation and manipulation of tissue.

[0004] In some embodiments, the present disclosure provides an apparatus for performing surgery, comprising a surgical robot including an endoscopic device extending from the surgical robot, the endoscopic device including an outer sheath, an inner sheath and a channel disposed inside the inner sheath. A guide tube is positioned inside the channel, the guide tube including a proximal end extending toward the surgical robot and a highly-curved distal end extending away from the surgical instrument. An inner tube is housed inside the guide tube, wherein the inner tube is axially moveable and rotatable relative to the guide tube. The highly-curved distal end of the guide tube includes a curvature between about 50 m ^A (-1) and about 100 m ^A (-1). [0005] In further embodiments, the highly-curved distal end of the guide tube includes a curvature between about 50 m ^A (-1) and about 100 m ^A (-1).

[0006] In additional embodiments, the present disclosure provides an apparatus for performing surgery, comprising a surgical robot including an endoscopic device extending from the surgical robot, the endoscopic device including an outer sheath, an inner sheath and first and second channels disposed inside the inner sheath. A first guide tube is positioned inside the channel, the first guide tube including a proximal end extending toward the surgical robot and a first highly-curved distal end extending away from the surgical robot. A second guide tube is positioned inside the channel, the second guide tube including a proximal end extending toward the surgical robot and a second highly-curved distal end extending away from the surgical robot. A first inner tube is housed inside the first guide tube, wherein the first inner tube is axially moveable and rotatable relative to the first guide tube. A second inner tube is housed inside the second guide tube, wherein the second inner tube is axially moveable and rotatable relative to the second guide tube. The first highly-curved distal end of the first guide tube includes a curvature between about 50 m ^A (-1 ) and about 100 m ^A (-1), and the second highly-curved distal end of the second guide tube includes a curvature between about 50 m ^A (-1) and about 100 m ^A (-1).

[0007] In further embodiments, the first highly-curved distal end of the first guide tube includes a curvature of about 72 m ^A (-1), and the second highly-curved distal end of the second guide tube includes a curvature of about 72 m ^A (-1 ).

[0008] Another objective of the present disclosure is to provide a device and methods for effectively manipulating tissue using first and second tools in a field of view near the tip of an endoscopic device.

[0009] Numerous other objects, advantages and features of the present disclosure will be readily apparent to those of skill in the art upon a review of the following drawings and description of a preferred embodiment.

BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a side perspective view of an embodiment of a minimally invasive surgery apparatus in accordance with the present invention.

[0011] FIG. 2 is a detail side view of the minimally invasive surgery apparatus of FIG. 1.

[0012] FIG. 3A is an exploded perspective view of an embodiment of the minimally invasive surgery apparatus of FIG. 1 .

[0013] FIG. 3B is a detail exploded perspective view of an embodiment of the minimally invasive surgery apparatus of FIG. 1 .

[0014] FIG. 4 is a perspective view of an embodiment of a tool cartridge apparatus for a minimally invasive surgery apparatus.

[0015] FIG. 5 is an exploded top view of an embodiment of a tube assembly of a minimally invasive surgery apparatus including an outer sheath, an inner sheath and a sheath insert including first and second channels. [0016] FIG. 6 is a partial cross-sectional view of an embodiment of a channel insert configured for positioning inside a sheath.

[0017] FIG. 7 is a perspective view of an embodiment of the distal end of an inner sheath including first and second channel openings and a channel bushing.

[0018] FIG. 8 is a perspective view of an embodiment of a sheath insert including first and second channels.

[0019] FIG. 9 is a perspective view of an embodiment of a steering plug for use on a sheath insert.

[0020] FIG. 10 is a perspective view of an embodiment of an inner sheath with first and second channels housed therein.

[0021] FIG. 11 is side view of an embodiment of an inner tube.

[0022] FIG. 12 is a side view of an embodiment of a highly-curved guide tube.

[0023] FIG. 13 is a side view of an embodiment of a combined inner tube and highly-curved guide tube.

[0024] FIG. 14 is a perspective view of an embodiment of a surgical robot apparatus including first and second highly-curved guide tubes and first and second inner tubes extending therefrom.

[0025] FIG. 15 is a partial cross-sectional view of an embodiment of a highly- curved guide tube inside a channel in a retracted position.

[0026] FIG. 16 is a side view of an embodiment of a guide tube with a doublecurve configuration.

[0027] FIG. 17 is a partial cross-sectional view of an embodiment of a guide tube with a double-curve configuration positioned inside a channel in a retracted position.

[0028] FIG. 18 is a perspective view of an embodiment of a field of view of a tissue workspace including first and second guide tubes and first and second inner tubes extending therefrom.

MODES FOR CARRYING OUT THE INVENTION

[0029] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that are embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific apparatus and methods described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims. [0030] In the drawings, not all reference numbers are included in each drawing, for the sake of clarity. In addition, positional terms such as “upper,” “lower,” “side,” “top,” “bottom,” etc. refer to the apparatus when in the orientation shown in the drawing. A person of skill in the art will recognize that the apparatus can assume different orientations when in use.

[0031] The present disclosure provides a minimally invasive surgery apparatus including a guide tube with a highly-curved distal end. The guide tube is housed in a longitudinal channel along the length of an endoscope or resectoscope type tube assembly. The channel many have a straight or a curved profile in various embodiments. The guide tube includes a highly-curved configuration that provides for superior triangulation in the workspace and manipulability for a surgeon to engage tissue near the distal end of an endoscope or resectoscope. The parameters of curvature at the distal end of the guide tube are optimized to provide enhanced performance.

[0032] The distal section of the guide tube is highly-curved and is configured for deployment into a tissue workspace beyond the distal tip of the endoscope inside a patient’s body. The distal section of the guide tube may be rotated and translated relative to the channel in which it is housed, and an inner tube including a surgical tool (such as an electrosurgery tool or cutting device) may be positioned inside the interior of the guide tube and extending out the distal end of the guide tube to access the tissue workspace within the field of view of a camera lens. The highly-curved distal end of the guide tube provides enhanced triangulation and dexterity in the workspace, and provides optimized performance for minimally invasive surgery.

[0033] As an example, an embodiment of a minimally invasive surgery apparatus 100 is shown generally in FIG. 1. The apparatus includes a surgical robot apparatus 10 mounted to a support 12. In some embodiments, support 12 includes a robotic arm 12a extending from a stationary base 12b. A mount 14 on the end of robotic arm 12a is configured for attachment to the surgical robot apparatus 10 via a brace 16 in some embodiments. Support 12 provides a programmable positioning device for precisely controlling the position and orientation of surgical robot apparatus 10 in three- dimensional space relative to a human or animal patient positioned on an operating table below the device.

[0034] An input console 200 is located remote from the support 12 and surgical robot apparatus 10. Input console 200 provides input to control one or more devices located on surgical robot apparatus 10. [0035] Referring further to FIG. 1 and FIG. 2, surgical robot apparatus 10 includes an interface 18 connecting a rigid tube assembly 20 with instrument base 22. Tube assembly 20 includes a longitudinal endoscope or resectoscope type structure comprising an outer sheath 26 and a plurality of tubes housed inside the outer sheath 26. One or more ports 27a, 27b, 27c are coupled to the tube assembly 20 to provide irrigation, suction or other functions during a surgical operation. Tube assembly 20 includes a distal end 21 oriented away from instrument base 22 for insertion into the tissue of a patient. A camera 24 is positioned on base 22, including a lens passing through the tube assembly 20 toward the distal end 21 for providing visualization of a tissue workspace adjacent distal end 21 when the tube assembly 20 is inserted into a patient’s body. Surgical robot apparatus 10 also includes an adapter 14a configured for attachment to mount 14, shown in FIG. 1.

[0036] Referring to FIG. 3A, camera 24 is positioned on instrument base 22 to provide real-time imagery to a remote display for a surgeon to view during a surgical procedure. Camera 24 includes a rod-shaped lens 25 extending through a longitudinal lens passage 80 inside the tube assembly 20 such that the lens provides a field of view including the tissue workspace immediately beyond the distal tip of the tube assembly. In some embodiments, lens passage 80 includes a rigid tube extending along the inside of the tube assembly 20 to protect the lens 25 as it is housed within, inserted and/or removed from the device. Lens passage 80 includes a funnel-shaped insertion port at its proximal end in some embodiments.

[0037] Referring further to FIG. 3A and 3B, tube assembly 20 includes an outer sheath 26 and an inner sheath 28. An annular plenum is defined between the outer surface of the inner sheath 28 and the inner surface of the outer sheath 26 such that gas or fluid may be transported through the plenum during a surgical procedure.

[0038] Referring further to FIG. 3A, in some embodiments, surgical robot apparatus 10 includes a first tool cartridge 60a and a second tool cartridge 60b. Each tool cartridge is configured as a modular part that can be installed in the instrument base 22. Each tool cartridge includes a drive mechanism configured to manipulate a tube array coupled to the cartridge. For example, first tool cartridge 60a is coupled to the proximal end of a first tube array 70a such that first tube array 70a extends away from the first tool cartridge 60a toward interface 18. Similarly, second tool cartridge 60b is coupled to the proximal end of a second tube array 70b such that the second tube array 70b extends away from the second tool cartridge 60b toward interface 18. Each tool cartridge 60a, 60b may be interchangeable with other like tool cartridges on instrument base 22. In some embodiments, each tool cartridge is disposable.

[0039] An embodiment of a tool cartridge 60 with an associated tube array 70 is shown in FIG. 4. Tool cartridge 60 includes a housing joined to the proximal end of the tube array 70. Tube array 70 includes a concentric tube array comprising a guide tube, or outer tube, 72 and an inner tube 74 positioned inside the guide tube 72. Guide tube 72 has a highly-curved distal end 78, and the inner tube 74 protrudes out of the distal tip 73 of the guide tube 72. Inner tube 74 includes a surgical tool 82 such as an electrosurgery tip, a cutting tool or a tissue manipulator protruding from its distal end in some embodiments. During a surgical procedure, inner tube 74 may be translated axially or rotated about its longitudinal axis independently of the guide tube 72. Highly- curved guide tube 72 steers the inner tube 74 to a desired location in the tissue workspace. Inner tube 74 is coupled to one or more internal drive components inside tool cartridge 60 to provide independent axial translation and rotation controls in some embodiments.

[0040] During use, guide tube 72 may also be translated and rotated by independent drive components inside tool cartridge 60. As such, due to the curved portion 78 of the guide tube 72, a range of motion may be achieved by rotating and translating guide tube 72 and inner tube 74 using independent drive components in tool cartridge 60.

[0041] The tube array 70 is housed inside a longitudinal channel assembly, or sheath insert 30, on the interior of an endoscope or resectoscope type device in some embodiments. As shown in FIG. 5, a sheath insert 30 includes a first channel 32 for housing a first concentric tube array 70a and a second substantially parallel channel 34 for housing a second concentric tube array 70b. Sheath insert 30 is positioned axially inside the endoscope or resectoscope inner sheath 28 to provide interior channels for housing a one or more concentric tube arrays. When assembled, first and second channels 32, 34 are positioned inside the inner sheath 28, and the outer sheath 26 is positioned on the exterior of the inner sheath 28. In some embodiments, first and second channels 32, 34 each include a hollow interior space forming a substantially round cross-sectional profile dimensioned such that each concentric tube array 70a, 70b will fit closely inside while allowing each guide tube 72, 172 to be rotated and axially translated independently inside its corresponding channel.

[0042] Referring to FIG. 6, an embodiment of a distal end of a sheath insert 30 is shown alongside an inner sheath on an endoscope or resectoscope. Sheath insert 30 includes a first channel 32 and a second channel 34. First and second channels 32, 34 diverge at the distal end. First channel 32 terminates at a first channel opening 38, and second channel 34 terminates at a second channel opening 48. A channel bushing 36 is disposed on the distal ends of first and second channels 32, 34 at the distal end of the sheath insert 30. Channel bushing 36 surrounds the distal ends of first and second channels 32, 34 in some embodiments. Channel bushing 36 provides support to the first and second channels 32, 34 in the region of divergence. Channel bushing 36 also interfaces with the interior wall of inner sheath 28 to properly align first and second channels 32, 34 at the desired location on the distal opening 50 of inner sheath 28. In some embodiments, channel bushing 36 includes a channel bushing width 49 substantially equal to the inner diameter 51 of inner sheath 28 at its distal opening 50. Channel bushing 36 comprises a polymer material in some embodiments. As shown in FIG. 6, a lens groove 53 provides a recess in channel bushing 36 shaped to accommodate the rod lens coupled to the camera. Channel bushing 36 and first and second channels 32, 34 are joined such that the entire assembly may be inserted axially into inner sheath 28, or may be pulled axially from inner sheath 28, following use. Sheath insert 30 is disposable in some embodiments. In other embodiments, sheath insert 30 is interchangeable with other like sheath inserts. For example, for a particular procedure, it may be desirable to use first and second channels 32, 34 having certain characteristics, such as inner diameter, channel shape or curvature at the distal end. However, for other procedures, it may be desirable to use first and second channels 32, 34 with different characteristics. Thus, using the system and methods of the present disclosure, a user may swap sheath inserts 30 having different characteristics for different operations.

[0043] Referring to FIG. 7, an embodiment of a sheath insert 28 including first and second channels 32, 34 is shown. First channel 32 opens at a first channel distal opening 38, and second channel 34 opens at a second channel distal opening 48. First and second channel distal openings 38, 48 are separated by a channel spacing 55. In some embodiments, channel spacing 55 is greater than the inner diameter of first or second channel 32, 34. In some embodiments, channel spacing 55 is greater than about twice the inner diameter of first channel 32 or second channel 34. First and second channel distal openings 38, 48 are spaced because both first and second channels 32, 34 diverge away from the axial centerline of inner sheath 28 in a curved orientation. As shown in FIG. 7, a lens may be positioned in the lens groove 53 inside inner sheath 28 above the channel bushing 38. [0044] Referring again to FIG. 5 and FIGS. 8 and 9, in some embodiments, a sheath insert 30 includes an interface 18 providing a rigid funnel-shaped structure connected at one end to the first and second channels 32, 34 and open at the other end for insertion of the tube arrays 70a, 70b and the rod lens 25 from camera 24. For example, in some embodiments, a steering plug 40 is positioned in interface 18. Steering plug 40 defines a first port 42 shaped to receive longitudinal insertion of first tube array 70a (coupled to first cartridge 60a in some embodiments), and a second port 44 shaped to receive longitudinal insertion of second tube array 70b (coupled to second cartridge 60b in some embodiments). Steering plug 40 also defines a lens insertion port 46 positioned to receive longitudinal insertion of a rod lens 25 in some embodiments.

[0045] Steering plug 40, as shown in FIG. 8, includes a sheath adapter 45 surrounding the proximal ends of first and second channels 32, 34. Sheath adapter 45 is similar in shape and function to channel bushing 36 in some embodiments. Sheath adapter 45 includes an outer diameter near the inner diameter of inner sheath 28, such that sheath adapter 45 fits closely along the interior wall of inner sheath 28 when received in the inner sheath 28. A lens guide 43 is defined on the sheath adapter, forming a groove to receive a portion of a lens passing longitudinally along the interior length of the inner sheath 28. An insert bushing 41 forms a rigid cylinder at the proximal end of the sheath adapter 45, configured for engagement with the inner sheath 28. In some embodiments, insert bushing 41 forms a seal around the interior of the inner sheath 28 on the endoscope or resectoscope.

[0046] As shown in FIG. 9, steering plug 40 may be formed as a unitary piece of a non-metal material, such as a polymer material. Steering plug 40 may be removed from interface 18 and replaced. In some embodiments, steering plug 40 is disposable. Steering plug 40 may be held in place inside interface 18 using a friction fit in some embodiments. Steering plug 40 may also fit closely inside the internal contours of interface 18 to form a seal between interface 18 and the steering plug 40 in some embodiments.

[0047] Steering plug 40 includes a first socket 132 shaped to receive the proximal end of first channel 32, and a second socket 134 shaped to receive the proximal end of second channel 34. Lens guide 43 defines a hollow passage in sheath adapter 45 shaped to receive passage of a lens, such as a fiber optic lens passing through the steering plug toward the distal end of the endoscope or resectoscope. As seen in FIG 10, the proximal end of first channel 32 may fit closely inside first socket 132, shown in FIG. 9, and similarly, the proximal end of second channel 34 may fit closely inside second socket 134. Thus, first and second channels 32, 34 may be in open communication with first port 42 and second port 44, respectively, shown in FIG. 5. A first tube array including a guide tube 72 and an inner tube 74 may be positioned into first port 42, through steering adapter 40, and into first channel 32. Similarly, a second tube array including a second guide tube 172 and a second inner tube 174 may be positioned into second port 44, through steering adapter 40, and into second channel 34.

[0048] Referring to FIGS. 11-13, the present disclosure provides a tube array including a substantially straight inner tube 74 positioned inside a guide tube 72 with a highly-curved distal end 73. Inner tube 74 includes a surgical tool positioned on its distal tip in some embodiments. Inner tube 74 is substantially straight along its length, although in some embodiments it may attain a slight curvature due to its use in a curved channel and/or in a curved guide tube. Because inner tube 74 is housed inside a guide tube 72 having a highly-curved end, inner tube 74 may gain some curvature during use by being slightly strained by the curved guide tube in which it is housed. In some embodiments, inner tube 74 has a distal end that attains a curvature less than about 10 m ^A (-1 ), having a radius greater than about 100 mm. In some embodiments, inner tube 74 includes a portion with a radius of between about 100 mm and about 500 mm.

[0049] Referring to FIG. 12, guide tube, or outer tube 72, includes a highly- curved distal end 73. Guide tube 72 comprises nitinol in some embodiments, and the curvature of the highly-curved distal end 73 of guide tube 72 is shapeset to a desired curvature to provide optimized performance. In some embodiments, the curvature of highly-curved distal end 73 of guide tube 72 is shapeset to a curvature between about 50 m ^A (-1) and about 100 m ^A (-1 ). In further embodiments, highly-curved distal end 73 of guide tube 72 is shapeset to a curvature between about 60 m ^A (-1) and about 80 m ^A (-1). In further embodiments, highly-curved distal end 73 of guide tube 72 is shapeset to a curvature of about 72 m ^A (-1) to provide optimized performance and manipulability in the workspace.

[0050] Referring further to FIG. 13, when inner tube 74 is positioned inside guide tube 72, the less-curved configuration of inner tube 74 slightly straightens distal end 73 of guide tube 72, further reducing the curvature of the distal end 73 of guide tube 72 to a curvature between about 60 m ^A (-1 ) and about 65 m ^A (-1 ). In further embodiments, the combined inner tube 74 and guide tube 72 includes a distal tip 73 with a combined effective curvature of about 63 m ^A (-1 ). In further embodiments, the present disclosure includes a tube array comprising a guide tube 72 and an inner tube 74 housed inside the guide tube 72, wherein tube array includes a combined curved distal tip with a combined effective curvature of greater than about 40 m ^A (-1) and less than about 100 m ^A (-1). In some embodiments, these parameters apply to both first guide tube 72 and first inner tube 74 housed inside first channel 32 and also second guide tube 172 and second inner tube 174 housed inside second channel 34.

[0051] Referring to FIG. 14, in some embodiments first and second guide tubes 72, 172 are both curved as set forth above. By providing first and second guide tubes 72, 172 each having a highly-curved distal end 73, 173, the curved ends may both extend simultaneously from the end of each respective channel 32, 34 at the end of an endoscope or resectoscope. The curvature of the first and second guide tubes 72, 172 moves the operational workspace of the tools closer to the tip of the endoscope and into the field of view. Additionally, the highly-curved distal ends of first and second guide tubes, along with the diverging curvatures of the first and second channels 32, 34, provide enhanced triangulation in the workspace. This allows the first and second inner tubes 74, 174 and corresponding first and second surgical tools 82, 182 to approach the centerline axis CL at a greater approach angle as compared to conventional surgical devices with lesser curvatures in the guide tubes 72 172 and channels 32, 34. In this configuration, first and second inner tubes 74, 174 may approach the workspace at greater triangulation angles and apply off-axis force vectors to better manipulate tissue in the workspace.

[0052] Some prior conventional devices include a guide tube with a curved distal end of about 3% strain. Such embodiments would not be considered highly-curved and would not be capable of the triangulation advantages of the present disclosure. In some embodiments, the present disclosure provides a first guide tube 72 and a second guide tube 172 each with a highly-curved distal end 73, 173 having strain greater than about 5%, forming an elbow-shaped configuration that provides an improved triangulation orientation for performing surgery, as shown in FIG 14. In some embodiments, each guide tube 72, 172 includes a highly-curved distal end 73, 173 with a strain of about 8%. In further embodiments, each guide tube 72, 172 includes a highly-curved distal end with a strain between about 8% and about 10%.

[0053] Inner tubes 74, 174 are provided with a lower curvature geometry in some embodiments to provide a natural feeling to a surgeon, due to common surgical tools having a reduced curvature, or substantially straight, orientation. For example, surgeons trained on laparoscopic equipment are used to having tools that translate axially into the workspace. For this reason, adapting surgical robots using endoscopic tools to have axial translation at the distal tip of the tool provides an intuitive approach for surgeons. As such, by providing inner tubes 74, 174 with a lesser curvature than the guide tube, that can be retracted or extended out the distal tip opening of guide tube 72, the present disclosure provides a system with an intuitive configuration for manipulating tissue using a tool on the distal tip of the inner tube 74 in a field of view of an endoscope or resectoscope.

[0054] Referring further to FIG. 14, although guide tubes with highly-curved distal ends provide enhanced operability, additional benefits are realized by providing first and second channels 32, 34 with curved, diverging distal ends 32a, 34a curving away from a centerline CL of the endoscope or resectoscope. For example, as shown in FIG. 14, first channel 32 extends longitudinally inside inner sheath 28, and first channel 32 includes a curved distal end 32a diverging away from the centerline CL. Similarly, second channel 34 extends longitudinally inside inner sheath 28 alongside first channel 32, and second channel 34 includes a curved distal end 34a diverging away from the centerline CL and away from first channel 32. First and second channels 32, 34 are tubes on sheath insert 30 in some embodiments. Each of first and second channel 32, 34 provide a passage for first and second guide tubes 72, 172, respectively. First guide tube 72 can translate axially and also rotate inside first channel 32, and second guide tube 172 can translate axially and also rotate inside second channel 34.

[0055] As shown in FIG. 14, by providing first and second channels 32, 34 with distal ends 32a, 34a curving away from each other and away from centerline CL, the highly-curved distal ends 73, 173 on guide tubes 72, 172 are able to extend away from the centerline CL at an angle when extended from the first and second distal end openings 38, 48 of each channel. In some embodiments, first and second channels 32, 34 include a curvature between about 15 m ^A (-1) and about 30 m ^A (-1 ). Such curvature ranges provide first and second channels 32, 34 each angled away from centerline CL at an angle of about 10 to 15 degrees. As such, the ranges of motion of first and second highly-curved guide tubes 72, 172 extending initially away from centerline CL due to curved channels 32, 34, and then back toward centerline CL following extension, provides superior triangulation in the workspace adjacent the end of the endoscope or resectoscope. Such a configuration also moves the nominal interaction point to a better position closer to the endoscope as opposed to similar configurations with straight channels. [0056] Referring to FIG. 15, in some embodiments when guide tube 72 is fully retracted in channel 32, the curvature of the highly-curved region 78 of guide tube 72 is constrained by the inner diameter of channel 32. From this position, the orientation of the distal end 73 of guide tube 72 projects along a linear extension axis 52 along which inner tube will travel if extended relative to guide tube 72. Due to the curvature of the guide tube 72 being constrained in the channel 32, a small volume of space 56 defined by the space between extension axis 52 and reference longitudinal axis 54 may be rendered inaccessible in the workspace region adjacent to the distal end of the endoscope.

[0057] Referring to FIG. 16, to overcome this problem, in some embodiments, guide tube 72 includes a reverse curve, or double-curvature, configuration including a first curved region 78a and a second curved region 78b. First curved region 78a includes a first radius of curvature R1 , and second curved region 78b includes a second radius of curvature R2. R1 and R2 are the same in some embodiments. Alternatively, R1 and R2 are different in other embodiments. First and second curved regions 78a, 78b, are curved in the same plane in some embodiments. First curved region 78a includes a first arc length, and second curved region 78b includes a second arc length less than the first arc length.

[0058] Referring to FIG. 17, a guide tube 72 including a double-curvature configuration defines an extension axis 52 angled toward reference longitudinal axis 54. As such, the second curved region 78b orients the inner tube toward the centerline when the guide tube 72 is fully retracted in channel 32. Such a configuration reduces the size of the space 56 rendered inaccessible to the inner tube 74 when extended along the extension axis 52.

[0059] In some embodiments, the second curved region 78b includes less than about 10.0 mm of the end of the guide tube 72. In further embodiments, the second curved region 78b includes a curvature of about 40 m ^A (-1 ) to provide an improved range of motion. In further embodiments, the second curved region 78b includes about 5.0 mm at the end of the guide tube 72, and includes a curvature of between about 35 m ^A (-1 ) and about 45 m ^A (-1 ). In some embodiments, the first curved region has a curvature of between about 50 m ^A (-1 ) and about 100 m ^A (-1 ). In further embodiments, the first curved region has a curvature of about 72 m ^A (-1 ), and second curved region has a curvature of about 40 m ^A (-1).

[0060] In further embodiments, the disclosure provides first and second guide tubes, each guide tube including a double-curvature configuration. In some embodiments, the first curved region of each guide tube includes a shape-set curvature between about 70 m ^A (-1) and about 75 m ^A (-1). The second curved region of each guide tube includes a shape-set curvature of about 40 m ^A (-1 ) along the last five millimeters of each guide tube.

[0061] Referring to FIG. 18, a field of view at the distal end of an endoscope as seen by a surgeon during a procedure is illustrated. The field of view includes a first highly-curved guide tube 72 and a first inner tube 74 extending therefrom. A second highly-curved guide tube 172 is also shown, including a second inner tube 174 extending therefrom. A first surgical tool 82 is disposed on the first inner tube 74, and a second surgical tool 182 is disposed on the second inner tube 174. First and second inner tubes 74, 174 may be axially translated and rotated relative to each respective guide tube 72, 172, and first and second inner tubes 74, 174 work cooperatively to manipulate tissue.

[0062] In further embodiments, the present invention provides a method of performing minimally invasive surgery. The method includes providing a surgical instrument including a base and a tube assembly. The tube assembly includes a channel and a guide tube disposed in the channel, wherein the guide tube is axially moveable and rotatable inside the channel. The guide tube includes a proximal section and a highly-curved distal section positioned away from the base. An inner tube can be housed inside the guide tube from the base to the distal tip of the tube assembly. The method further includes a step of rotating the proximal section of the guide tube to cause a corresponding rotation of the distal end of the guide tube; translating the guide tube to a desired location in a tissue workspace; translating the inner tube through the highly-curved guide tube until the distal end of the inner tube is guided to a desired location in the tissue workspace by the guide tube; and performing a surgical procedure using the surgical tool.

[0063] Thus, although there have been described particular embodiments of the present invention of a new and useful CONCENTRIC TUBE APPARATUS FOR MINIMALLY INVASIVE SURGERY, it is not intended that such references be construed as limitations upon the scope of this invention.