Abstract:
The present invention is a system comprising surgical units and operator interface units configured to provide multiple capabilities within a surgical environment, or within a surgical training environment. The system may provide such capabilities in a modular fashion, such that various functions may be accomplished through the addition or deletion of modules to the system to allow core components to be used to accomplish more than one function.

Description:
RELATED APPLICATIONS  
       [0001]     This patent application is a non-provisional application and claims priority from U.S. Provisional Patent Application Ser. No. 60/617,864, filed Oct. 12, 2004, and from U.S. patent application Ser. No. 10/652,722, filed on Dec. 17, 2003, the entire disclosures of which are incorporated by reference herein as if being set forth in their entireties, respectively. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to the field of robotic and computer assisted surgery, and more specifically to equipment and methods for robotic and computer assisted microsurgery.  
       BACKGROUND  
       [0003]     As shown in U.S. Patent 5,943,914 to Morimoto et al., “Master/slave” robots are known in which a surgeon&#39;s hand input is converted to a robotic movement. This is particularly useful for motion scaling wherein a larger motion in millimeters or centimeters by the surgeon&#39;s input is scaled into a smaller micron movement. Motion scaling has also been applied in cardiac endoscopy, and neurosurgical target acquisition brain biopsy (with a needle) but only in one degree of freedom, for example only for insertion, not for a full range of natural hand movement directions, i.e., not for all possible degrees of natural motion, Cartesian, spherical or polar coordinate systems or other coordinate systems.  
         [0004]     Further, in the prior art, surgical robots have been purposefully designed to eliminate the natural hand tremor motions of a surgeon&#39;s hand which is about a 50 micron tremor which oscillates with some regularity. The common presumption is that tremor motion creates inaccuracies in surgery. Therefore, robots have been tested which entirely eliminate the surgeon&#39;s natural hand tremor. See “A Steady-Hand Robotic System for Microsurgical Augmentation” Taylor et al.,  International Journal Of Robotics Research,  18(12):1201-1210 Dec. 1999, and also see “Robotic-assisted Microsurgery: A Feasibility Study in the Rat” LeRoux et al.,  Neurosurgery,  Mar. 2001, Volume 48, Number 3, page 584  
         [0005]     The way the primate body handles proprioceptive perception is via sensory feedback scaling (up and down) at the muscular level through the intrafusal fiber system of the Gamma efferent neural circuit. This system responds dynamically to changes in the anticipated muscle performance requirement at any instance by adjusting muscle tone with increased discharging for arousal and attention focusing states, and decrease output for resting and low attention states. The muscle spindle apparatus that does this is located in the muscle body, therefore feedback sensory scaling for muscle positioning, force, length and acceleration is partly programmed at the effector level in “hardware” of the body, i.e., the muscle itself. The evidence indicates a 10 cycle per second refresh rate for the human neurophysiological system in general.  
         [0006]     Joint position and fine motor function of the fingers occurs through unidirectional (50% of fibers) and bi-directional (50% of fibers) sensing at the joint structure. This coding is for rotation about an axis, but not for force and no clear speed of rotation feedback.  
         [0007]     Cutaneous receptors in the skin code for motion, by modulating higher centers in the thalamus and cerebral cortex. This can be timed to about 75 ms delays before motion occurs, including three neuronal synaptic transmission delays. These sensors are primarily distal to the joint of rotation and distal in the moving effector limb. Finally, the sense of contact is totally discrete from the above motion feedback sensory systems and the neural pathways and integration centers in the deep hemispheres and cerebral cortices function independent of motion to a large degree.  
         [0008]     Force reflectance sensing is also known in order to provide tactile or haptic feedback to a surgeon via an interface. See “Connecting Haptic Interface with a Robot” Bardofer et al., Melecon 200—10 th  Mediterranean Electrotechnical Conference, May 29-31 2000, Cyprus.  
         [0009]     However, in testing, all of these techniques ultimately slow down the actual surgery especially when performed in conjunction with a microscope for viewing the operation. The procedure time is typically increased by two to three times. See Robotic-assisted Microsurgery: A Feasibility Study in the Rat” cited above. It is believed that this affect is related to cognitive, perceptive and physiologic discrepancies between a surgeons expectations and the feedback and motions of a surgical robot in use.  
         [0010]     Another major design issue regards the choice between locating the surgeon in his normal operating position adjacent to the surgical field or locating the surgeon more remotely from the normal operating position at a terminal with a joystick and viewing screen for example. The prior art elects to locate the surgeon remotely from the traditional operational position about the head and to use monitors to display the operation to the surgeon.  
       SUMMARY OF THE INVENTION  
       [0011]     A system comprising surgical units and operator interface units configured to provide multiple capabilities within a surgical environment, or within a surgical training environment, is described. The system may provide such capabilities in a modular fashion, such that various functions may be accomplished through the addition or deletion of modules to the system to allow core components to be used to accomplish more than one function.  
         [0012]     An augmented surgical appliance is also described. The appliance includes a surgical unit, a controller unit for controlling the surgical unit, and at least a first and a second interface unit, the first and second interface units providing force feedback signals to operators of the interface units, where the first and said second interface units are communicably connected to the controller. The surgical unit is communicably connected to the controller, where the controller includes software for transferring control of the surgical unit from the first interface unit to the second interface unit upon receipt of an indication by an operator of the second interface unit that control of the surgical unit should be transferred from the first interface unit to the second interface unit.  
         [0013]     Further described is a method for utilizing such an augmented surgical appliance. The method includes the steps of communicably connecting the first and second interface units to the controller, communicably connecting the surgical unit to the controller, transferring control of the surgical unit to the first interface unit, initiating a surgical procedure utilizing the surgical unit, receiving from an operator of the second interface an instruction to transfer control of the surgical unit from the first interface unit to the second interface unit, transferring control of the surgical unit to the second interface unit when an instruction to transfer control of the surgical unit from the first interface unit to the second interface unit is received, and continuing the surgical procedure.  
         [0014]     Additionally, a computer readable media, which when executed by a computer implements a process providing control functionality to an augmented surgical appliance, is described. The process includes the steps of transferring control of the surgical unit to the first operator interface unit, receiving from an operator of the second operator interface unit an instruction to transfer control of the surgical unit from the first operator interface unit to the second operator interface unit, transferring control of the surgical unit to said second operator interface unit when an instruction to transfer control of the surgical unit from the first operator interface unit to the second operator interface unit is received, and continuing the surgical procedure. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0015]      FIG. 1  illustrates an augmented surgical interface according to the present invention, wherein two operator interface units are provided to alternately control a single augmented surgical unit.  
         [0016]      FIG. 2  is a notional process flowchart associated with a process for controlling the system of  FIG. 1 .  
         [0017]      FIG. 3  illustrates an augmented surgical interface system according to the present invention, wherein two augmented surgical units are controlled concurrently by a single operator interface unit.  
         [0018]      FIG. 4  illustrates a notional process flowchart associated with a process for controlling the system of  FIG. 3 .  
         [0019]      FIG. 5  illustrates an augmented surgical interface system according to the present invention, wherein a plurality of repeater interfaces are provided to allow operators in training to follow through a surgical procedure in process.  
         [0020]      FIG. 6  illustrates an augmented surgical interface system configured to provide a simulated surgical procedure, wherein the system includes a simulation generator, a first interface unit, a second interface unit, and repeater interface unit.  
         [0021]      FIG. 7  illustrates an augmented surgical interface system according to the present invention, wherein two operator interface units are provided to concurrently control two augmented surgical units via a controller incorporating functionality to deconflict motions of effectors associated with the surgical units. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]     The present invention relates to an augmented surgical appliance, using an operator interface  102  for a surgeon  104  combined with an augmented surgical unit portion  106  for performing surgical procedures. The interface and surgical unit portions are interconnected via a controller  108 , which receives input from the interface  102 , and converts the input to output performed by the surgical unit  106 . Feedback is provided to the interface  102  from the controller  108  in response to parameters measured at the surgical unit  106 .  
         [0023]     As shown in  FIG. 1 , the controller may be provided with a plurality of communications ports  110  for receiving input from one or more interfaces  102 ,  112 . The controller  108  may also be provided with one or more control ports  114  for providing control signals to the surgical unit  106 . As shown in  FIG. 1 , a single surgical unit  106  may be controlled by a plurality of interface unites  102 ,  112 , where the controller includes functionality for integrating the inputs from the multiple interface units  102 ,  112  in a coordinated fashion so as to prevent inadvertent signals being transmitted to the surgical unite  106 .  
         [0024]     In the embodiment as shown in  FIG. 1 , a single surgical unit  106  may be connected to a control port  114  associated with the controller  108 , while an instructor interface  102  and a student interface  112  are connected to communications ports  110  associated with the controller  108 .  
         [0025]     Such a system embodiment allows the instructor interface  102  to provide an instructor  104  to closely observe a surgical procedure, and assume control of the surgical unit  106  either for safety or instructional purposes. Such a process is shown in  FIG. 2 , wherein an instructor interface and a student interface have been provided  202 ,  204  in conjunction with a single surgical unit positioned  206  in the surgical field. At the start  212  of the surgical procedure, control of the surgical unit may be transferred  214  to the student interface.  
         [0026]     As the surgical procedure proceeds, the instructor may monitor  216  the procedure. If the instructor determines  220  that an over-ride of the student control of the surgical unit is indicated, the instructor may request  220  control of the surgical unit. The transfer may either be a transfer of motion control, may cause a suspension of further motion by locking the motion of the surgical unit, or may cause the surgical unit to translate any tools in use to a safe position.  
         [0027]     As it may be desirable to alternately freeze an instrument in position, hold an instrument in an as deployed condition, or cause the instrument to retract to a safe position, it may first be determined  222  whether the instructor desires the instrument to be retracted. If the instructor desires the instrument to be retracted, the controller may command  224  retraction of the instrument to a safe position. If the instructor does not desire to have the instrument retracted, it may then be determined  228  whether the instructor desires the instrument to be held in place. If the instructor desires the instrument to be held in place, the controller may command  230  that the instrument be held at a location until released by the instructor. Additionally, where an instrument is being held in place  230 , it may be determined  232  whether the instrument should be fixed as to condition (i.e., open or closed for a forceps), and if it is determined that it is desired to fix the instrument in a condition, the controller may command  234  that the instrument be fixed as to condition until released to the operator. Once the transfer parameters have been determined and commanded by the controller, control of the surgical unit may be transferred  236  to the instructor. This determination of transfer parameters may be extended to multiple effectors/instruments in use, i.e., parameters may be obtained for both an effector associated with a right hand control and for an effector associated with a left hand control. Transfer parameters may also be preconfigured, such as should an instructor require a rapid transfer of control, the instruments/effectors could be preconfigured to transfer as free, to a retracted position, to a hold position, and/or a fixed condition.  
         [0028]     The procedure may continue with the instructor in control until the instructor determines  240  that control should be transferred back to the student, at which point control may be transferred  214  to the student. Such transfer may additionally implement retraction of instruments in use, position hold for instruments in use, and a condition fix for instruments in use.  
         [0029]     As shown in  FIG. 3 , the system may be configured in the operating room to include two surgical units  302 ,  304 , associated with a single interface unit  306  via a controller  308 . The interface unit  306  may typically have two hand controllers  3310 ,  312 , corresponding to the left and right hands (not shown) of an operator  314 . The surgical units  302 ,  304  may typically have more than one effector  316  per surgical unit  302 ,  304  (two effectors per unit are shown), such that an operator  314  has four (4) possible effectors to control from two hand controllers  310 ,  312 . The use of multiple effectors allows a larger tool set to be available to the operator  314 .  
         [0030]     As shown in  FIG. 4 , the use of a greater number of effectors than hand controllers may be accomplished using the illustrated process. The surgical environment may be provided with an inter unit  406 , as well as be provided  402 ,  404  with first and second surgical units. The interface and surgical units may be communicably connected  410  to a controller. Control of the surgical units may be transferred  412  to the interface, at which point the operator may select  414  effectors and associate them with hand controllers. For example, an effector on the first surgical unit may be associated with the right hand controller, while an effector associated with the second surgical unit may be associated with the left hand controller. Such association may not only provide control authority over the given effector by a selected hand controller, it may also cause the controller to apply feedback parameters associated with the selected effector to the hand controller.  
         [0031]     Once the desired effector and hand controller associations have been selected  414 , the surgical procedure may be initiated  416 . If the operator determines  422  during the procedure that different effector assignments are desired (i.e., use of a new effector or re-assignment of an effector in use to a different hand controller is desired) the operator may identify  426  the new effector/hand control assignment to the controller.  
         [0032]     The position and condition of the effector will typically be of significance, such as where a tool for retracting flesh is being deselected. If the retractor were erroneously retracted, it could cause complications of the surgical procedure. Accordingly, it may be desirable to fix the effector in a position to allow a tool in use on the effector to remain in use after the effector is deselected. Alternately, it may be desirable to have the tool automatically retracted to a position outside of the surgical field. The surgeon operating the interface may thus indicate which response is desired. Additionally, where tools may have multiple degrees of freedom, such as a forcep tool having both position and clamping conditions, the operator may further indicate whether it is desired that the tool remain in the additional conditions, such as clamped or unclamped for a forcep tool. Again, the transfer condition of an instrument may be defined by the operator. If it is determined  426  that the operator desires an effector/instrument to be retracted prior to the transfer, effector/instrument may be retracted  428 . If it is determined  430  that the operator desires that a de-selected effector/instrument be held in position, the controller may issue commands to hold  423  the effector/instrument in position. Finally, if it is determined  434  that the operator desires that an effector/instrument be fixed as to condition, the controller may issue commands to fix the instrument in a given condition. Holding an instrument in position may be included when an effector/instrument is fixed as to position. If neither retract, hold, and/or fix as indicated, the operator may be queried to determine which condition the de-selected instrument should be left in. Once the condition of the deselected effector/instrument has been determined and accomplished, control of a selected effector/instrument may be assigned  440  to an identified control handle, and the surgical procedure may continue.  
         [0033]     Although the flowchart illustrates only a single cycle of a new effector/hand controller assignment occurring, it is contemplated that multiple reassignments may occur during a single surgical procedure.  
         [0034]     As shown in  FIG. 5 , the augmented surgical interface system may further be implemented to allow one or more operators in training  502 ,  504 ,  506  to follow through a surgical procedure being performed by a first surgeon  508 . The surgeon  508  may be provided with an interface unit  510  connected to a controller  512 . A surgical unit  514  having one or more effectors  516  may additionally be connected to the controller.  
         [0035]     Repeater interfaces  518 ,  520 ,  522  may be provided to allow operators in training  502 ,  504 ,  506  to follow through as the first surgeon  508  performs a procedure. In such a situation, the repeater interfaces would not have control authority over the surgical unit  514 , however would receive display and feedback parameters from the controller  512 , such that control handles  524  on the repeater interfaces  518 ,  520 ,  522  would mirror the positioning of the control handles  526  on the operator interface  510 . Accordingly, the feedback systems utilized in the interface units as described previously would cause the control handles  524  to mirror the motions of the first surgeon&#39;s control handles  526 . Additionally, the provision of display units  528  on the repeater interfaces  518 ,  520 ,  522  would allow the operators in training  502 ,  504 ,  506  to also see the visual presentations being provided to the first surgeon  508 .  
         [0036]     The repeater interfaces  518 ,  520 ,  522  may be the same as the interface unit  510 , with the controller  512  being used to prevent the repeater interfaces  518 ,  520 ,  522  from having any control authority over the surgical unit  514 . The use of common interface units may reduce the cost of implementing such a system on a hospital, such that where a hospital procures surgical units for more than one operating theater, the associated interface units may be aggregated in a single operating theater for a procedure which is to be followed through by operators in training, without the hospital having to procure additional equipment.  
         [0037]     As shown in  FIG. 6 , the modular nature of the controller  604 , surgical unit, and interface units also lend themselves to aggregation to form a simulator system  600 . A simulation generator  602  may be connected to a controller  604 . The simulation generator  602  may be provided with an environment model  606  for defining expected responses as a tool moves within a simulated surgical field. Such an environment model  606  may include parameters defining tissue position and consistency, as well as tissue response parameters to various surgical instruments which may be encountered during a simulated surgical procedure. The simulation generator  602  may further be provided with a display generator  608  for generating a simulated display of the surgical field, including tissue and tool positioning, as well as indicators and feedback that would be provided to a surgeon during a procedure.  
         [0038]     Finally, the simulation generator may further be provided with a kinematics model  610  that models the kinematic response of surgical instruments within the surgical field, such as contact information, acceleration forces and other motion forces which would be encountered during an actual procedure. The output of the simulation generator may be provided to the controller, such that the controller is provided with signals which would be consistent with the signals transmitted to the controller during an actual procedure. A first interface unit  612  may be designated as the controlling interface unit, such that commands provided by an operator  614  of the first interface unit would be used to provide command parameters for a simulated surgical procedure. A second interface unit  616  could be provided for a supervising surgeon or operator  618 , such that the training system of  FIG. 1  could be implemented in a simulated environment, such as may be desired to familiarize an operator in training  620  with the hand off procedures.  
         [0039]     Finally, a third interface unit  622  may also be provided to allow a second operator in training  624  to follow though the simulated procedure, or to step in upon the directions of the supervising surgeon or operator  618 . The third interface may alternately be limited such that control authority could not be transferred to the third interface unit  622 , effectively rendering the third interface unit to be a repeater interface unit.  
         [0040]     As shown in  FIG. 7 , it may be desired to utilize multiple surgical units  702 ,  704  in conjunction with multiple interface units  706 ,  708  during a surgical procedure. In such a situation, the ability to prevent interference between instruments associated with the different surgical units  702 ,  704  may be of paramount importance.  
         [0041]     The position of tools within the surgical field may be modeled as a function of the position of the surgical units to a fixed reference, such as the surgical table. The use of such referencing was discussed previously. By indexing both surgical units  702 ,  704  to the surgical table  710 , the resultant position of the surgical instruments could be determined by the controller  712  as a function of the position of the effectors to which the instruments are attached, as well as predetermined knowledge of the instruments themselves.  
         [0042]     Although the position of the tools is important in preventing interference between the tools, predictive analysis of the motion of the instruments themselves may provide a more effective function for the operators. The projected position of the tools may be based on the present motion and speed of the instruments, such that an increasing value can be determined indicating the likelihood of interference between the instruments. Such a value may be increased the sooner an interference may occur, i.e., a likely interference that will not occur for a longer period of time will be assigned a lower value than a likely interference which will occur sooner.  
         [0043]     An indication of the likelihood of contact may be presented to one or both of the operators during a procedure with multiple interface units. The indicator may be a visual or audible warning to the operators. Alternately, the controller may impose a scale function to the motion of the instruments as a function of the likelihood of the interference. For example, a velocity component of a commanded motion of an instrument may be reduced by an increasing factor the higher the likelihood of an interference. Thus, minimal scaling of the motion command would occur where the interference was of a lower likelihood, i.e., not expected to occur for a given amount of time. As the likelihood of the interference is expected to occur sooner, the scaling of the motion command may be increased to further slow the motion of the instrument, thus reducing the likelihood of an interference, as well as signaling the operator of the likelihood of the interference.  
         [0044]     Other variations and modifications of the present invention will be apparent to those of skill in the art, and it is the intent of the appended claims that such variations and modifications be covered. The particular values and configurations discussed above can be varied and are cited merely to illustrate a particular embodiment of the present invention and are not intended to limit the scope of the invention. It is contemplated that the use of the present invention can involve components having different characteristics as long as the principles of the invention are followed.