System, method, and apparatus for configuration, design, and operation of an active cannula robot

Abstract

The present invention relates to a system and apparatus for implementing a method for identifying tube parameters of a curved tube of an active cannula for operating on a target in a patient. The method includes the step (a) of acquiring a model of the patient anatomy including the target. The method also includes the step (b) of selecting a set of parameters characterizing a curved tube. The method also includes the step (c) of computing a workspace for an active cannula having the selected curved tube parameters. The method also includes the step (d) of comparing the workspace to the anatomical model to determine the degree to which an active cannula having the selected curved tube parameters covers the target. The method also includes the step (e) of repeating steps (b) through (d) through a defined number of curved tube parameter sets. The method also includes the step (f) of identifying the curved tube parameters that provide an active cannula with an optimal degree of target coverage.

We claim: 
     
         1 . An active cannula robot system for performing a surgical treatment on a target in a patient, the system comprising:
 an active cannula robot comprising an outer cannula tube and an inner cannula tube that extends coaxially within the outer cannula tube, the inner cannula tube having a distal curved end portion terminating at a tip, the robot being operable to cause translational movement of the outer and inner cannula tubes along the axis and to cause rotational movement of the inner cannula tube about the axis relative to the outer cannula tube to apply the treatment to the target; and   a controller configured to select a configuration of the curved end portion of the tube based on image data related to the target so that the tip can reach at least a threshold portion of the target through the translational and rotational movement.   
     
     
         2 . The system recited in  claim 1 , wherein the target comprises a clot resulting from an intracerebral hemorrhage, wherein the image data related to the clot is mapped to image data related to the patient's skull so that the position and orientation of the clot in the skull is known, the controller being configured to select the configuration of the curved end portion of the tube on the basis of the image data related to the clot. 
     
     
         3 . The system recited in  claim 2 , wherein the controller is configured to select the configuration of the curved end portion of the tube on the further basis of a surgical robot entry point on the patient's skull and a predetermined trajectory along which the outer and inner cannula tubes are inserted through the patient's skull into the patient's brain. 
     
     
         4 . The system recited in  claim 3 , further comprising a trajectory stem and an image guidance system that is operative to align the trajectory stem along the predetermined trajectory, wherein the controller is configured to select the configuration of the curved end portion of the inner cannula tube on the further basis of the trajectory. 
     
     
         5 . The system recited in  claim 2 , wherein the image data related to the clot and the image data related to the patient's skull comprises CT image data. 
     
     
         6 . The system recited in  claim 1 , wherein the robot is operable to retract the inner cannula tube into the outer cannula tube, the outer cannula tube having a straight configuration, the curved end portion deforming elastically and conforming to the straight configuration of the outer cannula tube when retracted into the outer cannula tube and returning resiliently to its curved configuration when extended from the outer cannula tube, the inner cannula tube being constructed so that the curved end portion when extended from within the outer cannula tube after being retracted within the outer cannula tube resumes its curved configuration. 
     
     
         7 . The system recited in  claim 6 , wherein the robot is operable to deliver the active cannula robot to the target in an axial direction with the inner cannula tube retracted into the outer cannula tube, the robot, thereafter extending the curved end portion of the inner cannula tube from the outer cannula tube into the target to treat the target. 
     
     
         8 . The system recited in  claim 2 , further comprising an aspirator operatively connected to the inner cannula tube, the aspirator being operable to apply suction via the inner cannula tube to evacuate the clot. 
     
     
         9 . The system recited in  claim 1 , wherein the controller is operable manually to control movement of the active cannula robot in combination with image guidance to move the tip of the inner cannula tube within the target. 
     
     
         10 . The system recited in  claim 1 , wherein the controller is operable automatically though open loop control to control movement of the active cannula robot to move the tip of the inner cannula tube within the target. 
     
     
         11 . The system recited in  claim 1 , further comprising a manual actuator comprising a first manual actuator operable to cause translational movement of the outer cannula tube along the axis, a second manual actuator operable to cause translational movement of the inner cannula tube along the axis, and a third manual actuator operable to impart rotation of the inner cannula tube about the axis. 
     
     
         12 . The system recited in  claim 1 , wherein the controller is configured to select a configuration of the curved end portion of the tube by:
 (a) acquiring an anatomical model of the patient anatomy including a target model of the target;   (b) selecting a set of curved tube parameters characterizing the curved end portion of the inner cannula tube;   (c) computing a workspace for the active cannula robot in which the inner cannula tube has the selected curved tube parameters;   (d) comparing the workspace to the target model to determine the degree to which an active cannula robot with an inner cannula tube having the selected curved tube parameters can cover the target;   (e) repeating steps (b) through (d) through a defined number of different curved tube parameter sets; and   (f) identifying curved tube parameter sets that, in combination, allow the active cannula robot to provide an optimal degree of target coverage.   
     
     
         13 . The system recited in  claim 12 , wherein the controller is configured to perform step (c) of computing a workspace by:
 mapping the joint space parameters of the active cannula robot to configuration space parameters in order to define a forward kinematic model for the active cannula robot;   discretizing the joint space of the active cannula robot to produce a discrete set of joint positions of the active cannula robot; and   solving the kinematic model for each discrete combination of joint positions to compute the workspace of the active cannula robot.   
     
     
         14 . The system recited in  claim 13 , wherein the controller is configured to perform step (d) of comparing the computed workspace to the clot model by:
 converting the target model to a discrete set of voxels;   computing an inner cannula tube tip position for each of the joint positions of the active cannula robot; and   evaluating each computed inner cannula tube tip position to determine whether it lies within a voxel of the target model.   
     
     
         15 . The system recited in  claim 12 , wherein the controller is configured to perform step (d) of comparing the workspace to the model by determining the degree to which the workspace overlaps the model. 
     
     
         16 . The system recited in  claim 12 , wherein the target comprises a clot resulting from an intracerebral hemorrhage in a patient, wherein the controller is configured to perform step (a) of acquiring a target model by acquiring a model of the clot mapped relative to a model of the patient's skull. 
     
     
         17 . The system recited in  claim 16 , wherein the controller is configured to perform the step of comparing the workspace to the model by determining a trajectory at which to advance the active cannula robot through the patient's skull and into the patient's brain to access the clot, and orienting the computed workspace within the clot according to the determined trajectory. 
     
     
         18 . The system recited in  claim 12 , wherein the defined number of curved tube parameter sets correspond to actual curved tube parameter sets for inner cannula tubes in a pre-existing set of tubes, wherein the controller is configured to select the curved tube parameter set identified in step (f) from the pre-existing set of tubes. 
     
     
         19 . The system recited in  claim 12 , wherein the defined number of curved tube parameter sets are theoretical parameter sets that are incremented sequentially through a predetermined range of discrete values, wherein the controller is configured to identify the curved tube parameters identified in step (f) as being parameters for subsequently constructing and configuring a curved tube of the active cannula robot. 
     
     
         20 . The system recited in  claim 12 , wherein the controller is configured to perform the steps of determining for each joint position whether the entire curve of the active cannula robot is positioned within the target model, and discarding joint positions in which any portion of the curve is positioned outside the target model.