WO2013106664A1

WO2013106664A1 - Systems and methods for robot-assisted transurethral exploration and intervention

Info

Publication number: WO2013106664A1
Application number: PCT/US2013/021167
Authority: WO
Inventors: Nabil Simaan; Andrea BAJO
Original assignee: Vanderbilt University
Priority date: 2012-01-13
Filing date: 2013-01-11
Publication date: 2013-07-18

Abstract

A robotic device for transurethral procedures in the bladder. The robotic device includes a central stem, a dexterous arm, and an actuator system. The central stem includes a first access channel and a second access channel positioned longitudinally along the central stem. The dexterous arm is at least partially positioned within the first access channel of the central stem and includes two working channels. A first camera system is positioned within the first working channel of the dexterous arm and a working tool is insertable through the second working channel. A second camera system is positioned at least partially within the second access channel of the central stem. The actuator system is configured to controllably extend and retract the dexterous arm through the first access channel of the central stem and to controllably bend the dexterous arm to position the working tool inside the bladder.

Description

SYSTEMS AND METHODS FOR ROBOT-ASSISTED TRANSURETHRAL EXPLORATION AND INTERVENTION

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 61/586,458 filed January 13, 2012, titled "SYSTEMS AND METHODS FOR ROBOT-ASSISTED TRANSURETHRAL EXPLORATION AND INTERVENTION," the entirety of which is incorporated herein by reference.

BACKGROUND

[0002] In 2010, there were 70,530 new cases of bladder cancer diagnosed in the United States and 14,680 deaths from bladder cancer. Of the newly diagnosed patients, more than 52,000 were men and 18,000 were women with most male patients above the age of 50. Approximately 70% of these new cases of bladder cancer were classified as non-muscle invasive cancer (NMIBC) which is initially treated with transurethral resection of bladder tumor (TURBT). In addition to being a standard surgical therapy for noninvasive bladder cancer, TURBT is also an integral part of the diagnostic evaluation of all bladder tumors.

[0003] Fig. 1 illustrates one example of a bladder resection procedure being performed with a resectoscope. The resectoscope is inserted through the urethra of a patient to access the bladder. Tumors in the bladder wall are resected through to the muscular layer of the bladder. Motion of the resectoscope is limited by the tissue and pubis anterior-superiorly and posterior-inferiorly. Medial and lateral motion is further hampered by the legs of the patient. The inserts in Fig. l depicts a tumor with both a broad front invasion in which the extent of the tumor is visible at the surface (A) and tentacular invasion in which the tumor invades below the urothelium and the margin for resection is invisible under white-light based imaging (B).

[0004] TURBT does, however, have its shortcomings. Initial TURBT is associated with imperfect clinical staging and incomplete tumor removal. An accurate pathological diagnosis, which is determined by depth of tumor invasion, is crucial for staging urothelial carcinomas. The stage of a patient's bladder cancer plays a key role in determining the patient's treatment and prognosis. The urologist is responsible for accurately sampling bladder tissue for evaluation, and should include muscularis propria (detrusor muscle) for adequate staging. Specimens missing muscle layers cannot confirm complete tumor resection.

[0005] The technical challenges of manual TURBT procedures are associated with considerable clinical ramifications. Although TURBT remains the gold standard for initial diagnosis and treatment of NMIBC, the early recurrence rate at three months can be as high as 45%. Furthermore, despite recommendations to perform complete resection of all visible tumors during an initial TURBT, a study of 150 consecutive patients with NMIBC undergoing repeat transurethral resection within 6 weeks of the initial procedure found 76% with residual tumor. Studies also indicate that at up to 5% of all TUR procedures result in perforations in the bladder due to full wall resection.

[0006] Furthermore, there is high variability in the clinical outcomes of TURBT procedures based on the skill of the surgeon and the technique used. In a combined analysis of seven randomized studies, the recurrence rate following TURBT for non-muscle invasive bladder cancer varied between institutions from 7% to 45%. This and other studies have been unable to attribute this variation to any other factor and instead conclude that the high variability in success rate is attributable to surgeon technique.

[0007] Lesion location can also influence resectability of tumors. In certain areas of the bladder, the ideal angle of approach to a tumor may be kinematically infeasible such that the bladder wall cannot be appropriately reached or traced. As illustrated in Fig. 1 , the anatomic constraints of the entrance through the urethra make access to anterior regions of the bladder difficult or infeasible without external manipulation. For approaching anterior aspects of the bladder, suprapubic pressure is applied to bring the bladder wall into the reachable workspace of the rigid resectoscope. However, these techniques have limited success with many patients - particularly in obese patients due to thick fat layers.

SUMMARY

[0008] In various embodiments, the invention described herein provides for reliable transurethral access to surfaces within the bladder. Embodiments also provide for improved surveillance and visual feedback to a surgeon or other user of the device and for mechanisms to prevent robotic tools from causing damage to the interior of the bladder. [0009] In one embodiment, the invention provides a robotic device for transurethral procedures in the bladder. The robotic device includes a central stem, a dexterous arm, and an actuator system. The central stem includes a first access channel and a second access channel positioned longitudinally along the central stem. The dexterous arm is at least partially positioned within the first access channel of the central stem and includes two working channels. A first camera system is positioned within the first working channel of the dexterous arm and a working tool is insertable through the second working channel. A second camera system is positioned at least partially within the second access channel of the central stem. The actuator system is configured to controllably extend and retract the dexterous arm through the first access channel of the central stem and to controllably bend the dexterous arm to position the working tool inside the bladder.

[0010] Some embodiments of the invention also provide a tool adjustment component positioned at the distal end of the dexterous arm. The tool adjustment component is controlled to adjust the angle of a working tool relative to the dexterous arm. In some embodiments, the tool adjustment component includes three circular segments arranged concentrically. The first segment is connected to the second segment by a first flexure positioned near an edge of the first segment and the second segment. The first flexure allows the second segment to be controllably tilted relative to the first segment on a first axis. The second segment is connected to the third segment by a second flexure positioned near an edge of the second segment and an edge of the third segment. The second flexure allows the second segment to be controllably tilted relative to the second segment on a second axis. The second axis is substantially perpendicular to the first axis.

[0011] In another embodiment, the invention provides a method of performing a medical procedure on an interior surface of a bladder. A rigid central stem is inserted transurethrally into the bladder of a patient. A dexterous arm is then extended from a distal end of the rigid central stem. The dexterous arm is controllably bent to position a distal end of the dexterous arm at a target site inside the bladder. Images of the target site are then captured by a first camera positioned at the distal end of the dexterous arm and a second camera positioned at the distal end of the rigid central stem. Commands are received from a user based on the displayed images. The commands tag the boundaries of a surface area inside the bladder where the medical procedure is to be performed. The tagged boundaries are then used to define the dimensions of a virtual fixture tangential to the surface area of the bladder. The operation and position of the dexterous arm and a working tool positioned at the distal end of the dexterous arm are controlled based on operation commands received from the user. However, the operation of the working tool is restricted in locations outside of the virtual fixture. In some embodiments, the working tool is entirely prevented from operating when positioned outside of the virtual fixture.

[0012] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Fig. 1 is a cross-sectional view of a resectoscope inserted into a bladder transurethrally.

[0014] Fig. 2 is a perspective view of a robotic device for transurethral bladder procedures according to one embodiment of the present invention.

[0015] Fig. 3 is a cross-section view of the robotic device of Fig. 2 inserted into a bladder transurethrally.

[0016] Fig. 4 is a perspective view of a dexterous arm of the robotic device of Fig. 2.

[0017] Fig. 5 is a cross-sectional view of a central stem of the robotic device of Fig. 2.

[0018] Fig. 6 is a cross-sectional view of the dexterous arm of the robotic device of Fig. 2.

[0019] Figs. 7A - 7E are perspective views of a laser ablation tool of the robotic device of Fig. 2 performing a resection.

[0020] Fig. 8 is a perspective view of a tool adjustment component coupled to the distal end of the dexterous arm of the robotic device of Fig. 2.

[0021] Fig. 9A is a top view of the tool adjustment component of Fig. 5.

[0022] Fig. 9B is a side view of the tool adjustment component of Fig. 5.

[0023] Fig. 10 is a block diagram of a control system for the robotic device of Fig. 2. [0024] Fig. 11 is a graph illustrating scaling factors used to define a resection depth limit.

[0025] Fig. 12 is a top view of a working tool of the robotic device of Fig. 2 operating within a defined virtual fixture.

DETAILED DESCRIPTION

[0026] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

[0027] Fig. 2 illustrates an example of a robotic device 100 for performing a procedure on the interior of a cavity. In particular, Fig. 2 illustrates the robotic device 100 configured to perform a transurethral procedure on the interior of a bladder. The robotic device includes a central stem 101 and a dexterous arm 103 extending through an access channel of the central stem 101. In some constructions, the central stem 101 is a hollow rigid shaft with a single concentric access channel. However, in other constructions, such as described below, the central stem is a rigid shaft that includes multiple access channels running along the length of the shaft. Alternatively, the central stem can be constructed of a bendable material that can provide stability while also complying somewhat to forces applied to the central stem by the human anatomy during usage.

[0028] The central stem 101 is connected to a first actuator component 105 by a bracket 107. The bracket 107 ensures that the central stem 101 does not move relative to the actuator 105. The actuator 105 is mechanically coupled to a push rod 109. When the actuator 105 moves the push rod 109 forward, the dexterous arm 103 is extended from the distal end of the central stem 101. When the push rod 109 is moved backward, the dexterous arm 103 retracts into the central stem 103. A second actuator component 11 1 is coupled to the top surface of the first actuator component 105. The second actuator component 11 1 controls movement of the dexterous arm 103.

[0029] The robotic device 100 is used to conduct observation of the interior of the bladder and to perform medical procedures, such as resection of tumors, on the interior surface of the bladder. With the dexterous arm 103 entirely retracted into the interior of the central stem 101, the central stem 101 is inserted through the urethra of the patient until the distal end of the central stem 101 is positioned within the bladder of the patient. After the distal end of the central stem 101 is positioned inside the bladder, the first actuator 105 extends the dexterous arm 103 out of the central stem 101. The second actuator system 1 11 can then move or bend the dexterous arm 103 to position the distal end of the dexterous arm 103 at a target site within the bladder. This controllable bending allows a working tool (such as those described in detail below) to be easily placed at target sites that historically have been difficult to reach with a rigid resectoscope, such as, for example, the anterior surface of the bladder. Fig. 3 illustrates the robotic device inserted into bladder of a patient

transurethrally with the dexterous arm extended.

[0030] Robotic devices that include actuators for extending a dexterous arm from a central stem and for adjusting the position of the extended dexterous arm have previously been described in International Publication No. WO 2012/015816.

[0031] Fig. 4 illustrates the dexterous arm 103 and the distal end of the central stem 101 in further detail. The central stem 101 includes four access channels 201, 203, 205, and 207. In the illustrated example, the dexterous arm 103 is positioned within and extends from the first access channel 201. A camera system 209 is positioned within the second access channel 203 of the central stem 101. The camera system 209 in this example is not extended or retracted through the access channel 203. Instead, the camera system 209 remains stationary relative to the central stem 101 and provides images from a fixed perspective of the dexterous arm 103 and various working tools as they operate within the bladder.

Alternatively, in some embodiments, a straight endoscope with an included lens is used to provide a view pointed to the side. By rotating the straight endoscope, a user can change the visible regions to provide a better view of the side walls of the bladder at a target location. Fig. 5 provides a cross-sectional view of the central stem 101 that better illustrates the location of the four access channels 201, 203, 205, and 207.

[0032] The central stem 101 in this example has a diameter of less than 9mm is sized to fit through the same diameter of a standard resectoscope outer sheath. The first access channel 201 in this example has a diameter of 5.2 mm and the second access channel 203 has a diameter of 2.8 mm. The two other access ports 205, 207 in this example are smaller than the first and second access channels and are used for saline input and output and to maintain insufflation of the bladder. [0033] The dexterous arm 103 includes three working channels 21 1, 213, and 215. In the illustrated example, a second camera system 217 is positioned within the first working channel 21 1, a grasper or biopsy cup 219 is positioned within the second working channel 213, and a laser ablation system 221 is positioned within the third working channel 215. While the first camera system 209 provides a fixed general view of the field, the fiberscope of the second camera system 217 provides a close view for surveillance and monitoring of fine resection. In some constructions, the fiberscope includes an integrated light. In other constructions, a separate light can be positioned in one of the three working channels of the dexterous arm 103.

[0034] The dexterous arm in this example is in the form of a continuum robot that includes multiple disks coupled together by linkages. As more clearly illustrated in Fig. 6, each disk 401 of the continuum robot includes a center hole 403. The center hole 403 is connected to a backbone shaft. Although the backbone shaft is flexible to allow the continuum robot to bend, it is fixedly connected to each disk 401 at the center hole 403 to ensure that each disk 401 remains at a fixed distance from the neighboring disks. Control fibers are extended through a series of perimeter holes 405, 407, and 409. One or more of the control fibers are controllably retracted by the second actuator system 1 11 to cause individual disks to tilt and to cause the continuum robot to bend as desired. Continuum robots that can be incorporated into this robotic system are known in the art as described, for example, in U.S. Patent Application Publication No. 2005/0059960 and U.S. Patent Application

Publication No. 201 1/0230894.

[0035] In the example of Fig. 4, the dexterous arm 103 includes two steerable snake-like segments that are each separately controllable for bending in two degrees-of-freedom. These two bending segments combined with the axial insertion degree-of-freedom provided by the push rod 109 provide a minimum of five degrees-of- freedom to locate the working tools at the distal end of the dexterous arm 103 in three-dimensions while specifying two orientation parameters with respect to the bladder wall. Furthermore, the working tools, such as the biopsy cup 219 can be extended from the working channel and rotated axially within the working channel to provide additional degrees-of-freedom.

[0036] As illustrated in Fig. 7, the laser ablation tool 221 can be aimed at a target surface by moving the position and orientation of the dexterous arm 103. In Fig. 7A, the dexterous arm positions the laser ablation tool at the center of a target area where tissue is to be removed. In Figs. 7B and 7C, the position and orientation of the dexterous arm is moved to aim the laser ablation tool at other locations of the target tissue. Fig. 7D shows the target tissue area before laser ablation while Fig. 7E shows the target area after laser ablation is completed using the robotic device described above.

[0037] Although the laser ablation tool 221 can be aimed at a target surface by adjusting the position and orientation of the dexterous arm, greater resection precision can be provided through independent control of the laser ablation tool 221. Independent control of the laser ablation tool 221 is achieved by a tool adjustment component 501 as illustrated in Fig. 8. The tool adjustment component 501 includes a two degree-of-freedom wrist that angulates the laser ablation fiber with respect to the distal end of the dexterous arm 103. As illustrated in Figs. 9A and 9B, three disk segments 601, 603, and 605 are positioned concentrically and attached by flexure joints 607 and 609. The flexure joints 607 and 609 are positioned at approximately 90 degree apart along the edge of the disk segments. This configuration allows the second disk 603 to be tilted relative to the first disk 601 along a first axis while the third disk 605 is tilted relative to the second disk 603 on a second axis. Each disk is pulled/pushed by a beam passing through one of the channels in the dexterous arm 103. Because the first and second axes are substantially perpendicular, the angle of the laser ablation tool 221 can be controlled with two degrees-of- freedom.

[0038] Fig. 10 illustrates a control system for the robotic device described above. A controller 701 includes a memory and a processor that executes software instructions stored on the memory. The controller 701 can be implemented as part of a stand-alone control system or integrated into a personal computer system. The controller 701 receives operational inputs from a user through a set of user input controls 703. The user input controls 703 can include, for example, one or more joystick controllers, pedals, buttons, and sliders. Based on the operational inputs, the controller 701 provides control signals to the first actuator 705 to control the extension and retraction of the dexterous arm and to the second actuator 707 to control the position and orientation of the dexterous arm. The controller 701 also provides control signals to the various working tools 709 positioned at the distal end of the dexterous arm. The controller 701 also provides control signals to an actuator 711 that controls the angle of a laser ablation tool by adjusting the tool adjustment component. The controller 701 also receives image data from both of the cameras 713 and displays the image data on a display 715. [0039] The control system for this robotic device can be integrated within a

telemanipulation system that includes a master interface (e.g., a Phantom Omni or any other haptic device with at least six degrees-of-freedom). The telemanipulation system can be implemented using the Matlab xPC Target real-time operating system with a host and a target computer. The host computer captures the mater interface input, relays the input signals to the target machine path planner, processes and displays a video stream for a steerable fiberscope and receives status and position orientation of the robot as relayed by the target computer. A surgeon using the system will have a standard fixed endoscope view and will be able to adjust the robot angle and lock it in position to that the central stem does not move relative to the patient. The surgeon also will be able to see the view from the steerable endoscope at the distal end of the dexterous arm.

[0040] The control system also provides several assistive modes to assist the surgeon in the process of surveillance and resection. In one assistive mode, virtual fixtures are defined by a user at the time of the procedure to restrict usage of working tools outside of a desired target area. In some constructions, assistive modes that define virtual fixtures operate by implementing telemanipulation control laws that define safety boundaries preventing the robot end effector (e.g., the dexterous arm and the working tools) from reaching undesired poses with the anatomy. The user manipulates the dexterous arm around the circumference of an area of interest to tag the circumference of a resection area. The user can also select one or more points inside the resection area to provide an indication of the depth of the resection area surface.

[0041] The circumference of the resection area and the depth reference points can be defined in a number of different ways. For example, the user can place the distal end of the dexterous arm in contact with the surface of the bladder and physically trace the

circumference of the resection area by moving the distal end of the dexterous arm across the surface of the bladder. The dexterous arm in other constructions can be fitted with a visible laser pointing device that can be used to trace the circumference of the resection area without physically contacting the surface of the bladder.

[0042] Alternatively, the user can place the distal end of the dexterous arm in contact with the bladder surface at a point along the circumference, register the point, and then remove the distal end from the surface of the bladder before moving the distal end to another point along the circumference. The points are registered by pressing a button or a pedal to indicate to the controller that the distal end of the dexterous arm is at an appropriate place. The robot controller records the tagged points and uses them to define a "least squares" surface fit with an associated boundary curve. The boundary curve is then used to define a virtual fixture in directions locally tangential to the bladder walls and the surface fit is used to define a depth of the virtual fixture.

[0043] The controller uses variable scaling a between the user input v_rf and robot commanded slave velocity v_dess as the robot tip approaches resection depth x=a where x>a designates the bladder tissue wall interior. For example, the scaling \_deSs = \ _rf where a is given by the equation:

where =Χ(α - χ)7α^η)

As illustrated in Fig. 11 , this scaling prevents tool penetration of more than distance a into the bladder wall. In equation (1), the parameter β = 0 if the user commands movement away from the bladder center. Otherwise, β =1. The scalar a_mj„ sets a minimal scaling factor for inward speeds at the virtual fixture wall x=a. Parameter n is a power coefficient that controls how aggressive the virtual fixture is.

[0044] The master interface reflects a force to the user according to the equation: fm = -||^f J de_Sm , \K\\ = fn + (l - /min > ^where t = \ - (Z (1) where f_m is the force applied by the master on the user's hand, n_ax and nin are maximal and minimal resistive force magnitudes, t is a non- dimensional parameter from 0 to 1.

[0045] Once the virtual fixture has been defined, the controller restricts the operation of the working tool in areas outside of the virtual fixture. As described above, the controller receives operational inputs from the user and controls the position and operation of the dexterous arm and the working tools based on the operational inputs. However, in some constructions, the controller user will prevent the user from moving the distal end of the dexterous arm outside of the virtual fixture when the working tools are in use. Similarly, the controller can prevent the user from operating/activating the working tools when the distal end of the dexterous arm is positioned outside of the virtual fixture.

[0046] Fig. 12 shows an image captured by the camera system 209 that is mounted on the distal end of the central stem 101 (see, Fig. 2). The image shows the dexterous arm 103 positioned to allow the working tools to interact with the tissue of the bladder. Two virtual fixtures 1201 and 1203 have been defined based on tags provided by the user. In this example, the dexterous arm 103 is positioned such that the working tools can be used to perform operations within the first virtual fixture 1201. As such, the controller prevents the user from moving the dexterous arm 103 outside of the first virtual fixture while the working tools are being used. When the working tool is deactivated, the dexterous arm 103 can be moved outside of the virtual fixture 1201. However, when the dexterous arm 103 is removed from the virtual fixture 103, the operation of the working tools is restricted until the dexterous arm 103 is moved back to one of the two virtual fixtures 1201 or 1203.

[0047] The robot control interface also allows the surgeon to toggle between fully independent kinematic redundancy resolution and a micro-macro dexterity mode. In the full independent redundancy resolution, the dexterous arm and the working tools are controlled by the controller based on user input while maximizing dexterity and distance from the limits of the joints in the dexterous arm and the push rod. In the micro-macro dexterity mode, the dexterous arm is controlled by the controller using user inputs while maintaining relative positions of the tooling and resection arms fixed with respect to the distal end of the dexterous arm. Once the user has placed the distal end of the dexterous arm at a target area, he provides an input that switches the system from the full independent redundancy resolution mode to the micro-macro dexterity mode so that he can perform small movements using the working tools and the tool adjustment component of the robotic device while the dexterous arm remains stationary and provides a local close-up view of the operation site using the fiberscope/camera chip.

[0048] The controller is also configured to provide assistance to the surgeon using image data captures by the camera systems. In another assistive mode, the controller presents a three-dimensional model of the bladder in a simplified representation. The simplified representation begins as a blank sphere. The three-dimensional model is then adjusted to include image data captured by the camera systems and, in some constructions, surface characteristics based on the direct kinematics of the dexterous arm as it interacts with the bladder surface. A surgeon is able to use the interface to replay video data captured by the camera and to tag spherical coordinates that are associated with areas of interest within the bladder. The surgeon can later select one of the tagged spherical coordinates and the controller will automatically adjust the dexterous arm into a pose that visualizes the selected surgical site.

[0049] Thus, the invention provides, among other things, a robotic device for performing transurethral surveillance and other procedures within the bladder of a patient. A controller is configured to provide assistive mechanisms to prevent the robotic device from causing damage outside of a target resection area and can also allow for automatic placement of a working tool at a tagged location. Various features and advantages of the invention are set forth in the following claims.

Claims

CLAIMS What is claimed is:

1. A robotic device for procedures in a cavity, the robotic device comprising:

a central stem including a first access channel and a second access channel positioned longitudinally along the central stem;

a dexterous arm at least partially positioned within the first access channel of the central stem, the dexterous arm including a first working channel and a second working channel;

a first camera system positioned within the first working channel of the dexterous arm;

a working tool insertable through the second working channel of the dexterous arm; a second camera system positioned at least partially within the second access channel of the central stem; and

an actuator system configured to

controllably extend and retract the dexterous arm through the first access channel of the central stem, and

controllably bend the dexterous arm to position the working tool inside the cavity.

2. The robotic device of claim 1 , wherein the working tool includes at least one of a grasper and a laser ablation system.

3. The robotic device of claim 1 , wherein the first camera system is coupled to the dexterous arm such that an image capture element of the first camera system positioned at a distal end of the dexterous arm moves with the dexterous arm when the dexterous arm is extended, retracted, or bent by the actuator system, and wherein the second camera system is coupled to the central stem such that an image capture element of the second camera system positioned at the distal end of the central stem remains stationary relative to the central stem.

4. The robotic device of claim 1, further comprising a tool adjustment component positioned at a distal end of the dexterous arm, wherein the tool adjustment component controllably adjusts an angle of a working tool relative to the dexterous arm.

5. The robotic device of claim 4, wherein the working tool includes a laser ablation system, and wherein the tool adjustment component controllably changes an angle the trajectory of radiation emitted from the laser ablation system relative to the first camera system.

6. The robotic device of claim 4, wherein the tool adjustment component includes a first segment, a second segment, and a third segment,

wherein the first segment is connected to the second segment by a first flexure positioned near an edge of the first segment and an edge of the second segment providing for controllable tilting of the second segment relative to the first segment on a first axis, and wherein the second segment is connected to the third segment by a second flexure positioned near an edge of the second segment and an edge of the third segment providing for controllable tilting of the third segment relative to the second segment on a second axis, the second axis being substantially perpendicular to the first axis.

7. The robotic device of claim 6, wherein the first segment, the second segment, and the third segment each include a circular component arranged concentrically relative to the other segments.

8. The robotic device of claim 1, wherein the actuator system is positioned proximal to a first end of the central stem and wherein a distal end of the dexterous arm extends beyond a distal end of the central stem when the dexterous arm is extended by the actuator system.

9. The robotic device of claim 8, wherein distal end of the dexterous arm does not extend beyond the distal end of the central stem when the dexterous arm is retracted by the actuator system.

10. The robotic device of claim 9, wherein a distal end of the dexterous arm is completely housed within the first access channel when the dexterous arm is retracted by the actuator system.

11. The robotic device of claim 1 , wherein the actuator system includes a first actuator component configured to extend and retract the dexterous arm and a second actuator component configured to bend the dexterous arm when the dexterous arm has been extended.

12. The robotic device of claim 1, wherein the dexterous arm includes a third working channel, wherein a light source is positioned within the third working channel of the dexterous arm.

13. The robotic device of claim 1, wherein the actuator system includes a controller configured to:

display images from at least one of the first camera system and the second camera system to a user;

receive a plurality of commands from the user, based on the images from at least one of the first camera system and the second camera system, tagging the boundaries of a surface area inside the cavity where a procedure is to be performed;

define dimensions of a virtual fixture tangential to the surface area of the cavity based on the tagged boundaries of the surface area inside the cavity received from the user; and control operation and position of the dexterous arm and the working tool based on operational commands received from the user, wherein the actuator system restricts the operation of the working tool in locations outside of the virtual fixture.

14. The robotic device of claim 13, wherein the controller is configured to prevent the working tool from operating when the working tool is positioned outside of the virtual fixture.

15. The robotic device of claim 13, wherein the plurality of commands received from the user for the purposes of tagging the boundaries of the surface area include commands to move the position of the dexterous arm around the circumference of the surface area.

16. The robotic device of claim 13, wherein the controller is configured to prevent the working tool from operating when telemanipulation commands received from a user attempt to drive the working tool outside of the virtual fixture.

17. The robotic device of claim 13, further comprising a visible laser pointing device, wherein the plurality commands received from the user for the purposes of tagging the boundaries of the surface area include commands to change the position of at least one of the dexterous arm and the laser pointing device to move the aim of the laser pointing device around the circumference of the surface area.

18. A method of performing a medical procedure on an interior surface of a bladder, the method comprising:

inserting a rigid central stem transurethrally into the bladder of a patient;

extending a dexterous arm from a distal end of the rigid central stem;

controllably bending the dexterous arm to position a distal end of the dexterous arm at a target site inside the bladder;

capturing an image of the target site by at least one of a camera system positioned at the distal end of the dexterous arm and a camera positioned at a distal end of the rigid central stem;

receiving a plurality of commands from a user, based on the image from at least one of the first camera system and the second camera system, tagging the boundaries of a surface area inside the bladder where the medical procedure is to be performed;

defining dimensions of a virtual fixture tangential to the surface area of the bladder based on the tagged boundaries of the surface area received from the user;

controlling operation and position of the dexterous arm and a working tool positioned at the distal end of the dexterous arm based on operational commands received from the user; and

restricting the operation of the working tool in locations outside of the virtual fixture.

19. The method of claim 18, wherein restricting the operation of the working tool in locations outside of the virtual fixture includes preventing the working tool from operating when the working tool is positioned outside of the virtual fixture.

20. The method of claim 18, wherein the plurality of commands received from the user for the purposes of tagging the boundaries of the surface area include commands to move the position of the dexterous arm around the circumference of the surface area.

21. The method of claim 18, wherein the plurality commands received from the user for the purposes of tagging the boundaries of the surface area include commands to change the position of at least one of the dexterous arm and a laser pointing device positioned at the distal end of the dexterous arm to move the aim of the laser pointing device around the circumference of the surface area.